From the upstream branch fw/extend_alloca. commit dc79f9aa56933dc8b475209f9a4059965b50ea26 Author: Florian Weimer Date: Sun Mar 1 18:29:47 2015 +0100 nscd restart: Use malloc instead of extend_alloca This introduces a separate function, read_cmdline, which reads the contents of /proc/self/cmdline into a heap-allocated buffer. [BZ #18023] * nscd/connections.c (read_cmdline): New function. (restart): Use it. Update comment. commit 9bed8b7fca7867d3027b66ce3985a75136aed013 Author: Florian Weimer Date: Sun Mar 1 15:14:19 2015 +0100 getgrent_next_nss (compat-initgroups): Remove alloca fallback If the caller-supplied buffer is not large enough, fall back directly malloc. The previous __libc_use_alloca check was incorrect because it did not take into account that extend_alloca may fail to merge allocations, so it would underestimate the stack space being used by roughly a factor of two. [BZ #18023] * nis/nss_compat/compat-initgroups.c (getgrent_next_nss): Fall back to malloc directly, without stack allocations. commit c95cc759ecb21f812872934ac55518aef28cf46b Author: Florian Weimer Date: Sun Mar 1 16:03:01 2015 +0100 _dl_map_object_deps: Use struct scratch_buffer instead of extend_alloca The function comment suggests that _dl_map_object_deps cannot use malloc, but it already allocates the l_initfini array on the heap, so the additional allocation should be acceptable. [BZ #18023] * elf/dl-deps.c (_dl_map_object_deps): Use struct scratch_buffer instead of extend_alloca. commit e38bff4db6f03d1fab732737f43a25160c3e4703 Author: Florian Weimer Date: Sun Mar 1 16:18:21 2015 +0100 _nss_nis_initgroups_dyn: Use struct scratch_buffer instead of extend_alloca Also adjusts the internal function get_uid. [BZ #18023] * nis/nss_nis/nis-initgroups.c (get_uid, _nss_nis_initgroups_dyn): Use struct scratch_buffer instead of extend_alloca. commit 8825d4709a686a870d313cc602d489ddd5354a08 Author: Florian Weimer Date: Sun Mar 1 18:55:33 2015 +0100 nscd: Use struct scratch_buffer instead of extend_alloca in most caches This replaces the ERANGE retry loops with loops which have heap fallback. Heap allocation might actually be required for extremely large NSS results. [BZ #18023] * nscd/grpcache.c (addgrbyX): Use struct scratch_buffer instead of extend_alloca. * nscd/hstcache.c (addhstbyX): Likewise. * nscd/pwdcache.c (addpwbyX): Likewise. * nscd/servicescache.c (addservbyX): Likewise. commit 140d8711d446f5193b04b56e714ddf8d0eddbf62 Author: Florian Weimer Date: Sun Mar 1 18:59:48 2015 +0100 nscd: Switch to struct scratch_buffer in adhstaiX The pre-allocation of the three scratch buffers increased the initial stack size somewhat, but if retries are needed, the previous version used more stack space if extend_alloca could not merge allocations. Lack of alloca accounting also means could be problematic with extremely large NSS responses, too. [BZ #18023] * nscd/aicache.c (addhstaiX): Use struct scratch_buffer instead of extend_alloca. commit 1af14faef808f03276766e5ee6d9ee7dc9053fba Author: Florian Weimer Date: Sun Mar 1 19:03:01 2015 +0100 getent: Switch to struct scratch_buffer in initgroups_keys The retry loop is slightly different here because getgrouplist provides size information, so scratch_buffer_set_array_size can be used to grow the buffer in a more precise fashion. [BZ #18023] * nss/getent.c (initgroups_keys): Use struct scratch_buffer instead of extend_alloca. commit 9b71d3b4df6dd4e49f7638d1d936c921c50fa3d9 Author: Florian Weimer Date: Sun Mar 1 19:09:00 2015 +0100 nss_files: Use struct scratch_buffer instead of extend_alloca In both _nss_files_gethostbyname3_r and _nss_files_initgroups_dyn, __libc_use_alloca was misused because it was not taken into account that extend_alloca can fail to merge allocations. [BZ #18023] * nss/nss_files/files-hosts.c (_nss_files_gethostbyname3_r): Use struct scratch_buffer instead of extend_alloca. * nss/nss_files/files-initgroups.c (_nss_files_initgroups_dyn): Likewise. commit 11c2a8bad9ca5fe510b73c0204b3dcf703f14d5c Author: Florian Weimer Date: Sun Mar 1 19:11:55 2015 +0100 gethostid (Linux variant): Switch to struct scratch_buffer Previously, extend_alloca was used without alloca accounting, which could have been problematic with large NSS results. [BZ #18023] * sysdeps/unix/sysv/linux/gethostid.c (gethostid): Use struct scratch_buffer instead of extend_alloca. commit 488063238ee5c87b66c6982b1b6d508e30e44386 Author: Florian Weimer Date: Sun Mar 1 19:48:31 2015 +0100 wordexp: Rewrite parse_tilde to use struct scratch_buffer [BZ #18023] * posix/wordexp.c (parse_tilde): Use struct scratch_buffer instead of extend_alloca. commit 683543bbb3e2c1b17554c4096d00c2980f39a802 Author: Florian Weimer Date: Sun Mar 1 23:22:45 2015 +0100 Remove macros extend_alloca, extend_alloca_account [BZ #18023] And also the helper macro stackinfo_alloca_round. extend_alloca simply does not work on x86_64 and current i386 because its peculiar stack alignment rules. Here's an analysis of the _dl_fini situation (before the removal of extend_alloca). Dump of assembler code for function _dl_fini: <+0>: push %rbp <+1>: mov %rsp,%rbp <+4>: push %r15 <+6>: push %r14 <+8>: push %r13 <+10>: push %r12 <+12>: push %rbx <+13>: sub $0x38,%rsp The function pushes 6 registers on the stack and allocates 0x38 bytes, which means that %rsp is a multiple of 16 after function prologue. The initial alloca allocation does not change %rsp alignment: <+210>: shr $0x4,%rcx <+214>: shl $0x4,%rcx <+218>: sub %rcx,%rsp %r15 is the address of the previous stack allocation, it is used below. This is the extend_alloca reallocation branch: <+734>: add $0xf,%rdx <+738>: and $0xfffffffffffffff0,%rdx <+742>: lea 0x1e(%rdx),%rcx <+746>: shr $0x4,%rcx <+750>: shl $0x4,%rcx <+754>: sub %rcx,%rsp <+757>: lea 0xf(%rsp),%rcx <+762>: and $0xfffffffffffffff0,%rcx <+766>: lea (%rcx,%rdx,1),%rsi <+770>: cmp %rsi,%r15 <+773>: je 0x7f963940b673 <_dl_fini+787> <+775>: mov %rdx,-0x58(%rbp) <+787>: add %rdx,-0x58(%rbp) (a) %rdx, the new requested size, is rounded up to a multiple of 16 (+734, %+738), and the result is stored in %rdx@738. (b) %rdx@738 + 31 is rounded down to a multiple of 16, the result is stored in rcx@750 (+742, +746, +750). So %rcx@750 == %rdx@738 + 16. (c) %rcx@750 bytes are allocated on the stack (+754). %rsp is rounded upwards to a multiple of 16, result is stored in %rcx@762 (+757, +762). This does not change the value of %rsp because it already was a multiple of 16. (d) %rsi@766 == %rcx@762 + %rdx@738 is compared against %r15. But this comparison is always false because we allocated 16 extra bytes on the stack in (b), which were reserved for the alignment in (c), but in fact unused. We are left with a gap in stack usage, and the comparison is always false. (@XXX refers to register values after executing the instruction at offset +XXX.) If the alignment gap was actually used because of different alignment for %rsp, then the comparison failure would still occur because the gap would not have been added after this reallocation, but before the previous allocation. As a result, extend_alloca is never able to merge allocations. It also turns out that the interface is difficult to use, especially in cojunction with alloca account (which is rarely optional). [BZ #18023] * include/alloca.h (stackinfo_alloca_round, extend_alloca, extend_alloca_account): Remove. diff --git a/elf/dl-deps.c b/elf/dl-deps.c index c975fcffd7735f9e..df7fc442ae1a80aa 100644 --- a/elf/dl-deps.c +++ b/elf/dl-deps.c @@ -27,6 +27,7 @@ #include #include #include +#include #include @@ -181,9 +182,8 @@ _dl_map_object_deps (struct link_map *map, /* Pointer to last unique object. */ tail = &known[nlist - 1]; - /* No alloca'd space yet. */ - struct link_map **needed_space = NULL; - size_t needed_space_bytes = 0; + struct scratch_buffer needed_space; + scratch_buffer_init (&needed_space); /* Process each element of the search list, loading each of its auxiliary objects and immediate dependencies. Auxiliary objects @@ -213,13 +213,12 @@ _dl_map_object_deps (struct link_map *map, if (l->l_searchlist.r_list == NULL && l->l_initfini == NULL && l != map && l->l_ldnum > 0) { - size_t new_size = l->l_ldnum * sizeof (struct link_map *); - - if (new_size > needed_space_bytes) - needed_space - = extend_alloca (needed_space, needed_space_bytes, new_size); - - needed = needed_space; + /* l->l_ldnum includes space for the terminating NULL. */ + if (!scratch_buffer_set_array_size + (&needed_space, l->l_ldnum, sizeof (struct link_map *))) + _dl_signal_error (ENOMEM, map->l_name, NULL, + N_("cannot allocate dependency buffer")); + needed = needed_space.data; } if (l->l_info[DT_NEEDED] || l->l_info[AUXTAG] || l->l_info[FILTERTAG]) @@ -438,8 +437,11 @@ _dl_map_object_deps (struct link_map *map, struct link_map **l_initfini = (struct link_map **) malloc ((2 * nneeded + 1) * sizeof needed[0]); if (l_initfini == NULL) - _dl_signal_error (ENOMEM, map->l_name, NULL, - N_("cannot allocate dependency list")); + { + scratch_buffer_free (&needed_space); + _dl_signal_error (ENOMEM, map->l_name, NULL, + N_("cannot allocate dependency list")); + } l_initfini[0] = l; memcpy (&l_initfini[1], needed, nneeded * sizeof needed[0]); memcpy (&l_initfini[nneeded + 1], l_initfini, @@ -457,6 +459,8 @@ _dl_map_object_deps (struct link_map *map, } out: + scratch_buffer_free (&needed_space); + if (errno == 0 && errno_saved != 0) __set_errno (errno_saved); diff --git a/include/alloca.h b/include/alloca.h index fd90664f0a17cd6d..c0b83954436ed4c1 100644 --- a/include/alloca.h +++ b/include/alloca.h @@ -23,57 +23,17 @@ libc_hidden_proto (__libc_alloca_cutoff) #include -#ifndef stackinfo_alloca_round -# define stackinfo_alloca_round(l) (((l) + 15) & -16) -#endif - -#if _STACK_GROWS_DOWN -# define extend_alloca(buf, len, newlen) \ - (__typeof (buf)) ({ size_t __newlen = stackinfo_alloca_round (newlen); \ - char *__newbuf = __alloca (__newlen); \ - if (__newbuf + __newlen == (char *) (buf)) \ - len += __newlen; \ - else \ - len = __newlen; \ - __newbuf; }) -#elif _STACK_GROWS_UP -# define extend_alloca(buf, len, newlen) \ - (__typeof (buf)) ({ size_t __newlen = stackinfo_alloca_round (newlen); \ - char *__newbuf = __alloca (__newlen); \ - char *__buf = (char *) (buf); \ - if (__buf + len == __newbuf) \ - { \ - len += __newlen; \ - __newbuf = __buf; \ - } \ - else \ - len = __newlen; \ - __newbuf; }) -#else -# define extend_alloca(buf, len, newlen) \ - __alloca (((len) = (newlen))) -#endif - #if defined stackinfo_get_sp && defined stackinfo_sub_sp # define alloca_account(size, avar) \ ({ void *old__ = stackinfo_get_sp (); \ void *m__ = __alloca (size); \ avar += stackinfo_sub_sp (old__); \ m__; }) -# define extend_alloca_account(buf, len, newlen, avar) \ - ({ void *old__ = stackinfo_get_sp (); \ - void *m__ = extend_alloca (buf, len, newlen); \ - avar += stackinfo_sub_sp (old__); \ - m__; }) #else # define alloca_account(size, avar) \ ({ size_t s__ = (size); \ avar += s__; \ __alloca (s__); }) -# define extend_alloca_account(buf, len, newlen, avar) \ - ({ size_t s__ = (newlen); \ - avar += s__; \ - extend_alloca (buf, len, s__); }) #endif # endif /* !_ISOMAC */ diff --git a/nis/nss_nis/nis-initgroups.c b/nis/nss_nis/nis-initgroups.c index a47b4d7ada0fe37b..d6ab289b291861c5 100644 --- a/nis/nss_nis/nis-initgroups.c +++ b/nis/nss_nis/nis-initgroups.c @@ -16,7 +16,6 @@ License along with the GNU C Library; if not, see . */ -#include #include #include #include @@ -27,6 +26,7 @@ #include #include #include +#include #include "nss-nis.h" #include @@ -120,27 +120,30 @@ internal_getgrent_r (struct group *grp, char *buffer, size_t buflen, static int get_uid (const char *user, uid_t *uidp) { - size_t buflen = sysconf (_SC_GETPW_R_SIZE_MAX); - char *buf = (char *) alloca (buflen); + struct scratch_buffer tmpbuf; + scratch_buffer_init (&tmpbuf); while (1) { struct passwd result; struct passwd *resp; - int r = getpwnam_r (user, &result, buf, buflen, &resp); + int r = getpwnam_r (user, &result, tmpbuf.data, tmpbuf.length, &resp); if (r == 0 && resp != NULL) { *uidp = resp->pw_uid; + scratch_buffer_free (&tmpbuf); return 0; } if (r != ERANGE) break; - buf = extend_alloca (buf, buflen, 2 * buflen); + if (!scratch_buffer_grow (&tmpbuf)) + return 1; } + scratch_buffer_free (&tmpbuf); return 1; } @@ -254,8 +257,6 @@ _nss_nis_initgroups_dyn (const char *user, gid_t group, long int *start, } struct group grpbuf, *g; - size_t buflen = sysconf (_SC_GETPW_R_SIZE_MAX); - char *tmpbuf; enum nss_status status; intern_t intern = { NULL, NULL, 0 }; gid_t *groups = *groupsp; @@ -264,15 +265,21 @@ _nss_nis_initgroups_dyn (const char *user, gid_t group, long int *start, if (status != NSS_STATUS_SUCCESS) return status; - tmpbuf = __alloca (buflen); + struct scratch_buffer tmpbuf; + scratch_buffer_init (&tmpbuf); while (1) { while ((status = - internal_getgrent_r (&grpbuf, tmpbuf, buflen, errnop, + internal_getgrent_r (&grpbuf, tmpbuf.data, tmpbuf.length, errnop, &intern)) == NSS_STATUS_TRYAGAIN && *errnop == ERANGE) - tmpbuf = extend_alloca (tmpbuf, buflen, 2 * buflen); + if (!scratch_buffer_grow (&tmpbuf)) + { + status = NSS_STATUS_TRYAGAIN; + *errnop = errno; + goto done; + } if (status != NSS_STATUS_SUCCESS) { @@ -331,6 +338,7 @@ done: intern.start = intern.start->next; free (intern.next); } + scratch_buffer_free (&tmpbuf); return status; } diff --git a/nscd/aicache.c b/nscd/aicache.c index 6f7b038021746e22..c2ac71f2b9647caa 100644 --- a/nscd/aicache.c +++ b/nscd/aicache.c @@ -28,6 +28,7 @@ #include #include #include +#include #include "dbg_log.h" #include "nscd.h" @@ -111,10 +112,13 @@ addhstaiX (struct database_dyn *db, int fd, request_header *req, if (ctx == NULL) no_more = 1; - size_t tmpbuf6len = 1024; - char *tmpbuf6 = alloca (tmpbuf6len); - size_t tmpbuf4len = 0; - char *tmpbuf4 = NULL; + struct scratch_buffer tmpbuf6; + scratch_buffer_init (&tmpbuf6); + struct scratch_buffer tmpbuf4; + scratch_buffer_init (&tmpbuf4); + struct scratch_buffer canonbuf; + scratch_buffer_init (&canonbuf); + int32_t ttl = INT32_MAX; ssize_t total = 0; char *key_copy = NULL; @@ -127,6 +131,7 @@ addhstaiX (struct database_dyn *db, int fd, request_header *req, int status[2] = { NSS_STATUS_UNAVAIL, NSS_STATUS_UNAVAIL }; int naddrs = 0; size_t addrslen = 0; + char *canon = NULL; size_t canonlen; @@ -141,12 +146,17 @@ addhstaiX (struct database_dyn *db, int fd, request_header *req, at = &atmem; rc6 = 0; herrno = 0; - status[1] = DL_CALL_FCT (fct4, (key, &at, tmpbuf6, tmpbuf6len, + status[1] = DL_CALL_FCT (fct4, (key, &at, + tmpbuf6.data, tmpbuf6.length, &rc6, &herrno, &ttl)); if (rc6 != ERANGE || (herrno != NETDB_INTERNAL && herrno != TRY_AGAIN)) break; - tmpbuf6 = extend_alloca (tmpbuf6, tmpbuf6len, 2 * tmpbuf6len); + if (!scratch_buffer_grow (&tmpbuf6)) + { + rc6 = ENOMEM; + break; + } } if (rc6 != 0 && herrno == NETDB_INTERNAL) @@ -224,41 +234,38 @@ addhstaiX (struct database_dyn *db, int fd, request_header *req, while (1) { rc6 = 0; - status[0] = DL_CALL_FCT (fct, (key, AF_INET6, &th[0], tmpbuf6, - tmpbuf6len, &rc6, &herrno, &ttl, + status[0] = DL_CALL_FCT (fct, (key, AF_INET6, &th[0], + tmpbuf6.data, tmpbuf6.length, + &rc6, &herrno, &ttl, &canon)); if (rc6 != ERANGE || herrno != NETDB_INTERNAL) break; - tmpbuf6 = extend_alloca (tmpbuf6, tmpbuf6len, 2 * tmpbuf6len); + if (!scratch_buffer_grow (&tmpbuf6)) + { + rc6 = ENOMEM; + break; + } } if (rc6 != 0 && herrno == NETDB_INTERNAL) goto out; - /* If the IPv6 lookup has been successful do not use the - buffer used in that lookup, use a new one. */ - if (status[0] == NSS_STATUS_SUCCESS && rc6 == 0) - { - tmpbuf4len = 512; - tmpbuf4 = alloca (tmpbuf4len); - } - else - { - tmpbuf4len = tmpbuf6len; - tmpbuf4 = tmpbuf6; - } - /* Next collect IPv4 information. */ while (1) { rc4 = 0; - status[1] = DL_CALL_FCT (fct, (key, AF_INET, &th[1], tmpbuf4, - tmpbuf4len, &rc4, &herrno, + status[1] = DL_CALL_FCT (fct, (key, AF_INET, &th[1], + tmpbuf4.data, tmpbuf4.length, + &rc4, &herrno, ttl == INT32_MAX ? &ttl : NULL, canon == NULL ? &canon : NULL)); if (rc4 != ERANGE || herrno != NETDB_INTERNAL) break; - tmpbuf4 = extend_alloca (tmpbuf4, tmpbuf4len, 2 * tmpbuf4len); + if (!scratch_buffer_grow (&tmpbuf4)) + { + rc4 = ENOMEM; + break; + } } if (rc4 != 0 && herrno == NETDB_INTERNAL) @@ -284,13 +291,11 @@ addhstaiX (struct database_dyn *db, int fd, request_header *req, cfct = __nss_lookup_function (nip, "getcanonname_r"); if (cfct != NULL) { - const size_t max_fqdn_len = 256; - char *buf = alloca (max_fqdn_len); char *s; int rc; - if (DL_CALL_FCT (cfct, (key, buf, max_fqdn_len, &s, - &rc, &herrno)) + if (DL_CALL_FCT (cfct, (key, canonbuf.data, canonbuf.length, + &s, &rc, &herrno)) == NSS_STATUS_SUCCESS) canon = s; else @@ -319,18 +324,20 @@ addhstaiX (struct database_dyn *db, int fd, request_header *req, addrfamily = AF_INET6; } - size_t tmpbuflen = 512; - char *tmpbuf = alloca (tmpbuflen); int rc; while (1) { rc = __gethostbyaddr2_r (addr, addrlen, addrfamily, - &hstent_mem, tmpbuf, tmpbuflen, + &hstent_mem, + canonbuf.data, canonbuf.length, &hstent, &herrno, NULL); if (rc != ERANGE || herrno != NETDB_INTERNAL) break; - tmpbuf = extend_alloca (tmpbuf, tmpbuflen, - tmpbuflen * 2); + if (!scratch_buffer_grow (&canonbuf)) + { + rc = ENOMEM; + break; + } } if (rc == 0) @@ -559,6 +566,10 @@ next_nip: dh->usable = false; } + scratch_buffer_free (&tmpbuf6); + scratch_buffer_free (&tmpbuf4); + scratch_buffer_free (&canonbuf); + return timeout; } diff --git a/nscd/connections.c b/nscd/connections.c index 5f91985859b3026a..49e4bf0f54daa5d8 100644 --- a/nscd/connections.c +++ b/nscd/connections.c @@ -1331,64 +1331,83 @@ request from '%s' [%ld] not handled due to missing permission"), } } - -/* Restart the process. */ -static void -restart (void) +static char * +read_cmdline (size_t *size) { - /* First determine the parameters. We do not use the parameters - passed to main() since in case nscd is started by running the - dynamic linker this will not work. Yes, this is not the usual - case but nscd is part of glibc and we occasionally do this. */ - size_t buflen = 1024; - char *buf = alloca (buflen); - size_t readlen = 0; int fd = open ("/proc/self/cmdline", O_RDONLY); - if (fd == -1) + if (fd < 0) + return NULL; + size_t current = 0; + size_t limit = 1024; + char *buffer = malloc (limit); + if (buffer == NULL) { - dbg_log (_("\ -cannot open /proc/self/cmdline: %s; disabling paranoia mode"), - strerror (errno)); - - paranoia = 0; - return; + close (fd); + errno = ENOMEM; + return NULL; } - while (1) { - ssize_t n = TEMP_FAILURE_RETRY (read (fd, buf + readlen, - buflen - readlen)); - if (n == -1) + if (current == limit) { - dbg_log (_("\ -cannot read /proc/self/cmdline: %s; disabling paranoia mode"), - strerror (errno)); + char *newptr; + if (2 * limit < limit + || (newptr = realloc (buffer, 2 * limit)) == NULL) + { + free (buffer); + close (fd); + errno = ENOMEM; + return NULL; + } + buffer = newptr; + limit *= 2; + } + ssize_t n = TEMP_FAILURE_RETRY (read (fd, buffer + current, + limit - current)); + if (n == -1) + { + int e = errno; + free (buffer); close (fd); - paranoia = 0; - return; + errno = e; + return NULL; } - - readlen += n; - - if (readlen < buflen) + if (n == 0) break; - - /* We might have to extend the buffer. */ - size_t old_buflen = buflen; - char *newp = extend_alloca (buf, buflen, 2 * buflen); - buf = memmove (newp, buf, old_buflen); + current += n; } close (fd); + *size = current; + return buffer; +} + + +/* Restart the process. */ +static void +restart (void) +{ + /* First determine the parameters. We do not use the parameters + passed to main() because then nscd would would use the system + libc after restarting even if it was started by a non-system + dynamic linker during glibc testing. */ + size_t readlen; + char *cmdline = read_cmdline (&readlen); + if (cmdline == NULL) + { + dbg_log (_("\ +cannot open /proc/self/cmdline: %m; disabling paranoia mode")); + paranoia = 0; + return; + } /* Parse the command line. Worst case scenario: every two characters form one parameter (one character plus NUL). */ char **argv = alloca ((readlen / 2 + 1) * sizeof (argv[0])); int argc = 0; - char *cp = buf; - while (cp < buf + readlen) + for (char *cp = cmdline; cp < cmdline + readlen;) { argv[argc++] = cp; cp = (char *) rawmemchr (cp, '\0') + 1; @@ -1405,6 +1424,7 @@ cannot change to old UID: %s; disabling paranoia mode"), strerror (errno)); paranoia = 0; + free (cmdline); return; } @@ -1416,6 +1436,7 @@ cannot change to old GID: %s; disabling paranoia mode"), ignore_value (setuid (server_uid)); paranoia = 0; + free (cmdline); return; } } @@ -1433,6 +1454,7 @@ cannot change to old working directory: %s; disabling paranoia mode"), ignore_value (setgid (server_gid)); } paranoia = 0; + free (cmdline); return; } @@ -1481,6 +1503,7 @@ cannot change to old working directory: %s; disabling paranoia mode"), dbg_log (_("cannot change current working directory to \"/\": %s"), strerror (errno)); paranoia = 0; + free (cmdline); /* Reenable the databases. */ time_t now = time (NULL); diff --git a/nscd/grpcache.c b/nscd/grpcache.c index 0ed8e656b2ae8ff9..3515971ea02d4192 100644 --- a/nscd/grpcache.c +++ b/nscd/grpcache.c @@ -16,7 +16,6 @@ You should have received a copy of the GNU General Public License along with this program; if not, see . */ -#include #include #include #include @@ -32,6 +31,7 @@ #include #include #include +#include #include "nscd.h" #include "dbg_log.h" @@ -448,12 +448,12 @@ addgrbyX (struct database_dyn *db, int fd, request_header *req, look again in the table whether the dataset is now available. We simply insert it. It does not matter if it is in there twice. The pruning function only will look at the timestamp. */ - size_t buflen = 1024; - char *buffer = (char *) alloca (buflen); + struct group resultbuf; struct group *grp; - bool use_malloc = false; int errval = 0; + struct scratch_buffer tmpbuf; + scratch_buffer_init (&tmpbuf); if (__glibc_unlikely (debug_level > 0)) { @@ -463,43 +463,24 @@ addgrbyX (struct database_dyn *db, int fd, request_header *req, dbg_log (_("Reloading \"%s\" in group cache!"), keystr); } - while (lookup (req->type, key, &resultbuf, buffer, buflen, &grp) != 0 + while (lookup (req->type, key, &resultbuf, + tmpbuf.data, tmpbuf.length, &grp) != 0 && (errval = errno) == ERANGE) - { - errno = 0; - - if (__glibc_unlikely (buflen > 32768)) - { - char *old_buffer = buffer; - buflen *= 2; - buffer = (char *) realloc (use_malloc ? buffer : NULL, buflen); - if (buffer == NULL) - { - /* We ran out of memory. We cannot do anything but - sending a negative response. In reality this should - never happen. */ - grp = NULL; - buffer = old_buffer; - - /* We set the error to indicate this is (possibly) a - temporary error and that it does not mean the entry - is not available at all. */ - errval = EAGAIN; - break; - } - use_malloc = true; - } - else - /* Allocate a new buffer on the stack. If possible combine it - with the previously allocated buffer. */ - buffer = (char *) extend_alloca (buffer, buflen, 2 * buflen); - } + if (!scratch_buffer_grow (&tmpbuf)) + { + /* We ran out of memory. We cannot do anything but sending a + negative response. In reality this should never + happen. */ + grp = NULL; + /* We set the error to indicate this is (possibly) a temporary + error and that it does not mean the entry is not available + at all. */ + errval = EAGAIN; + break; + } time_t timeout = cache_addgr (db, fd, req, keystr, grp, uid, he, dh, errval); - - if (use_malloc) - free (buffer); - + scratch_buffer_free (&tmpbuf); return timeout; } diff --git a/nscd/hstcache.c b/nscd/hstcache.c index 344a2b3052cc6ee0..95bff9b390495920 100644 --- a/nscd/hstcache.c +++ b/nscd/hstcache.c @@ -34,6 +34,7 @@ #include #include #include +#include #include "nscd.h" #include "dbg_log.h" @@ -463,11 +464,8 @@ addhstbyX (struct database_dyn *db, int fd, request_header *req, look again in the table whether the dataset is now available. We simply insert it. It does not matter if it is in there twice. The pruning function only will look at the timestamp. */ - int buflen = 1024; - char *buffer = (char *) alloca (buflen); struct hostent resultbuf; struct hostent *hst; - bool use_malloc = false; int errval = 0; int32_t ttl = INT32_MAX; @@ -487,46 +485,30 @@ addhstbyX (struct database_dyn *db, int fd, request_header *req, dbg_log (_("Reloading \"%s\" in hosts cache!"), (char *) str); } - while (lookup (req->type, key, &resultbuf, buffer, buflen, &hst, &ttl) != 0 + struct scratch_buffer tmpbuf; + scratch_buffer_init (&tmpbuf); + + while (lookup (req->type, key, &resultbuf, + tmpbuf.data, tmpbuf.length, &hst, &ttl) != 0 && h_errno == NETDB_INTERNAL && (errval = errno) == ERANGE) - { - errno = 0; - - if (__glibc_unlikely (buflen > 32768)) - { - char *old_buffer = buffer; - buflen *= 2; - buffer = (char *) realloc (use_malloc ? buffer : NULL, buflen); - if (buffer == NULL) - { - /* We ran out of memory. We cannot do anything but - sending a negative response. In reality this should - never happen. */ - hst = NULL; - buffer = old_buffer; - - /* We set the error to indicate this is (possibly) a - temporary error and that it does not mean the entry - is not available at all. */ - h_errno = TRY_AGAIN; - errval = EAGAIN; - break; - } - use_malloc = true; - } - else - /* Allocate a new buffer on the stack. If possible combine it - with the previously allocated buffer. */ - buffer = (char *) extend_alloca (buffer, buflen, 2 * buflen); - } + if (!scratch_buffer_grow (&tmpbuf)) + { + /* We ran out of memory. We cannot do anything but sending a + negative response. In reality this should never + happen. */ + hst = NULL; + /* We set the error to indicate this is (possibly) a temporary + error and that it does not mean the entry is not + available at all. */ + h_errno = TRY_AGAIN; + errval = EAGAIN; + break; + } time_t timeout = cache_addhst (db, fd, req, key, hst, uid, he, dh, h_errno == TRY_AGAIN ? errval : 0, ttl); - - if (use_malloc) - free (buffer); - + scratch_buffer_free (&tmpbuf); return timeout; } diff --git a/nscd/pwdcache.c b/nscd/pwdcache.c index 4c3ab660211f2b28..3f816ee0b06ae385 100644 --- a/nscd/pwdcache.c +++ b/nscd/pwdcache.c @@ -16,7 +16,6 @@ You should have received a copy of the GNU General Public License along with this program; if not, see . */ -#include #include #include #include @@ -32,6 +31,7 @@ #include #include #include +#include #include "nscd.h" #include "dbg_log.h" @@ -426,12 +426,11 @@ addpwbyX (struct database_dyn *db, int fd, request_header *req, look again in the table whether the dataset is now available. We simply insert it. It does not matter if it is in there twice. The pruning function only will look at the timestamp. */ - size_t buflen = 1024; - char *buffer = (char *) alloca (buflen); struct passwd resultbuf; struct passwd *pwd; - bool use_malloc = false; int errval = 0; + struct scratch_buffer tmpbuf; + scratch_buffer_init (&tmpbuf); if (__glibc_unlikely (debug_level > 0)) { @@ -441,45 +440,26 @@ addpwbyX (struct database_dyn *db, int fd, request_header *req, dbg_log (_("Reloading \"%s\" in password cache!"), keystr); } - while (lookup (req->type, key, &resultbuf, buffer, buflen, &pwd) != 0 + while (lookup (req->type, key, &resultbuf, + tmpbuf.data, tmpbuf.length, &pwd) != 0 && (errval = errno) == ERANGE) - { - errno = 0; - - if (__glibc_unlikely (buflen > 32768)) - { - char *old_buffer = buffer; - buflen *= 2; - buffer = (char *) realloc (use_malloc ? buffer : NULL, buflen); - if (buffer == NULL) - { - /* We ran out of memory. We cannot do anything but - sending a negative response. In reality this should - never happen. */ - pwd = NULL; - buffer = old_buffer; - - /* We set the error to indicate this is (possibly) a - temporary error and that it does not mean the entry - is not available at all. */ - errval = EAGAIN; - break; - } - use_malloc = true; - } - else - /* Allocate a new buffer on the stack. If possible combine it - with the previously allocated buffer. */ - buffer = (char *) extend_alloca (buffer, buflen, 2 * buflen); - } + if (!scratch_buffer_grow (&tmpbuf)) + { + /* We ran out of memory. We cannot do anything but sending a + negative response. In reality this should never + happen. */ + pwd = NULL; + /* We set the error to indicate this is (possibly) a temporary + error and that it does not mean the entry is not available + at all. */ + errval = EAGAIN; + break; + } /* Add the entry to the cache. */ time_t timeout = cache_addpw (db, fd, req, keystr, pwd, c_uid, he, dh, errval); - - if (use_malloc) - free (buffer); - + scratch_buffer_free (&tmpbuf); return timeout; } diff --git a/nscd/servicescache.c b/nscd/servicescache.c index 49d9d0dece186c1b..53868c97b56af367 100644 --- a/nscd/servicescache.c +++ b/nscd/servicescache.c @@ -16,7 +16,6 @@ You should have received a copy of the GNU General Public License along with this program; if not, see . */ -#include #include #include #include @@ -25,6 +24,7 @@ #include #include #include +#include #include "nscd.h" #include "dbg_log.h" @@ -374,12 +374,11 @@ addservbyX (struct database_dyn *db, int fd, request_header *req, look again in the table whether the dataset is now available. We simply insert it. It does not matter if it is in there twice. The pruning function only will look at the timestamp. */ - size_t buflen = 1024; - char *buffer = (char *) alloca (buflen); struct servent resultbuf; struct servent *serv; - bool use_malloc = false; int errval = 0; + struct scratch_buffer tmpbuf; + scratch_buffer_init (&tmpbuf); if (__glibc_unlikely (debug_level > 0)) { @@ -389,43 +388,24 @@ addservbyX (struct database_dyn *db, int fd, request_header *req, dbg_log (_("Reloading \"%s\" in services cache!"), key); } - while (lookup (req->type, key, &resultbuf, buffer, buflen, &serv) != 0 + while (lookup (req->type, key, &resultbuf, + tmpbuf.data, tmpbuf.length, &serv) != 0 && (errval = errno) == ERANGE) - { - errno = 0; - - if (__glibc_unlikely (buflen > 32768)) - { - char *old_buffer = buffer; - buflen *= 2; - buffer = (char *) realloc (use_malloc ? buffer : NULL, buflen); - if (buffer == NULL) - { - /* We ran out of memory. We cannot do anything but - sending a negative response. In reality this should - never happen. */ - serv = NULL; - buffer = old_buffer; - - /* We set the error to indicate this is (possibly) a - temporary error and that it does not mean the entry - is not available at all. */ - errval = EAGAIN; - break; - } - use_malloc = true; - } - else - /* Allocate a new buffer on the stack. If possible combine it - with the previously allocated buffer. */ - buffer = (char *) extend_alloca (buffer, buflen, 2 * buflen); - } + if (!scratch_buffer_grow (&tmpbuf)) + { + /* We ran out of memory. We cannot do anything but sending a + negative response. In reality this should never + happen. */ + serv = NULL; + /* We set the error to indicate this is (possibly) a temporary + error and that it does not mean the entry is not available + at all. */ + errval = EAGAIN; + break; + } time_t timeout = cache_addserv (db, fd, req, key, serv, uid, he, dh, errval); - - if (use_malloc) - free (buffer); - + scratch_buffer_free (&tmpbuf); return timeout; } diff --git a/nss/getent.c b/nss/getent.c index e609e5f9bb62a70f..f8cee703e337c4b2 100644 --- a/nss/getent.c +++ b/nss/getent.c @@ -39,6 +39,7 @@ #include #include #include +#include /* Get libc version number. */ #include @@ -477,30 +478,34 @@ netgroup_keys (int number, char *key[]) static int initgroups_keys (int number, char *key[]) { - int ngrps = 100; - size_t grpslen = ngrps * sizeof (gid_t); - gid_t *grps = alloca (grpslen); - if (number == 0) { fprintf (stderr, _("Enumeration not supported on %s\n"), "initgroups"); return 3; } + struct scratch_buffer tmpbuf; + scratch_buffer_init (&tmpbuf); + for (int i = 0; i < number; ++i) { + ssize_t ngrps = tmpbuf.length / sizeof (gid_t); int no = ngrps; int n; - while ((n = getgrouplist (key[i], -1, grps, &no)) == -1 + while ((n = getgrouplist (key[i], -1, tmpbuf.data, &no)) == -1 && no > ngrps) { - grps = extend_alloca (grps, grpslen, no * sizeof (gid_t)); - ngrps = no; + if (!scratch_buffer_set_array_size (&tmpbuf, no, sizeof (gid_t))) + { + fprintf (stderr, _("Could not allocate group list: %m\n")); + return 3; + } } if (n == -1) return 1; + const gid_t *grps = tmpbuf.data; printf ("%-21s", key[i]); for (int j = 0; j < n; ++j) if (grps[j] != -1) @@ -508,6 +513,8 @@ initgroups_keys (int number, char *key[]) putchar_unlocked ('\n'); } + scratch_buffer_free (&tmpbuf); + return 0; } diff --git a/nss/nss_compat/compat-initgroups.c b/nss/nss_compat/compat-initgroups.c index 74414f4622880b31..540eee863c85dea3 100644 --- a/nss/nss_compat/compat-initgroups.c +++ b/nss/nss_compat/compat-initgroups.c @@ -261,7 +261,6 @@ getgrent_next_nss (ent_t *ent, char *buffer, size_t buflen, const char *user, overwrite the pointer with one to a bigger buffer. */ char *tmpbuf = buffer; size_t tmplen = buflen; - bool use_malloc = false; for (int i = 0; i < mystart; i++) { @@ -270,29 +269,26 @@ getgrent_next_nss (ent_t *ent, char *buffer, size_t buflen, const char *user, == NSS_STATUS_TRYAGAIN && *errnop == ERANGE) { - if (__libc_use_alloca (tmplen * 2)) - { - if (tmpbuf == buffer) - { - tmplen *= 2; - tmpbuf = __alloca (tmplen); - } - else - tmpbuf = extend_alloca (tmpbuf, tmplen, tmplen * 2); - } - else - { - tmplen *= 2; - char *newbuf = realloc (use_malloc ? tmpbuf : NULL, tmplen); - - if (newbuf == NULL) - { - status = NSS_STATUS_TRYAGAIN; - goto done; - } - use_malloc = true; - tmpbuf = newbuf; - } + /* Check for overflow. */ + if (__glibc_unlikely (tmplen * 2 < tmplen)) + { + __set_errno (ENOMEM); + status = NSS_STATUS_TRYAGAIN; + goto done; + } + /* Increase the size. Make sure that we retry + with a reasonable size. */ + tmplen *= 2; + if (tmplen < 1024) + tmplen = 1024; + if (tmpbuf != buffer) + free (tmpbuf); + tmpbuf = malloc (tmplen); + if (__glibc_unlikely (tmpbuf == NULL)) + { + status = NSS_STATUS_TRYAGAIN; + goto done; + } } if (__builtin_expect (status != NSS_STATUS_NOTFOUND, 1)) @@ -320,7 +316,7 @@ getgrent_next_nss (ent_t *ent, char *buffer, size_t buflen, const char *user, status = NSS_STATUS_NOTFOUND; done: - if (use_malloc) + if (tmpbuf != buffer) free (tmpbuf); } diff --git a/nss/nss_files/files-initgroups.c b/nss/nss_files/files-initgroups.c index 8af0d4d36a400f0e..b441d8345f8a7a24 100644 --- a/nss/nss_files/files-initgroups.c +++ b/nss/nss_files/files-initgroups.c @@ -16,7 +16,6 @@ License along with the GNU C Library; if not, see . */ -#include #include #include #include @@ -25,6 +24,7 @@ #include #include #include +#include enum nss_status _nss_files_initgroups_dyn (const char *user, gid_t group, long int *start, @@ -46,9 +46,8 @@ _nss_files_initgroups_dyn (const char *user, gid_t group, long int *start, enum nss_status status = NSS_STATUS_SUCCESS; bool any = false; - size_t buflen = 1024; - void *buffer = alloca (buflen); - bool buffer_use_malloc = false; + struct scratch_buffer tmpbuf; + scratch_buffer_init (&tmpbuf); gid_t *groups = *groupsp; @@ -67,26 +66,16 @@ _nss_files_initgroups_dyn (const char *user, gid_t group, long int *start, } struct group grp; - int res = _nss_files_parse_grent (line, &grp, buffer, buflen, errnop); + int res = _nss_files_parse_grent (line, &grp, + tmpbuf.data, tmpbuf.length, errnop); if (res == -1) { - size_t newbuflen = 2 * buflen; - if (buffer_use_malloc || ! __libc_use_alloca (buflen + newbuflen)) + if (!scratch_buffer_grow (&tmpbuf)) { - void *newbuf = realloc (buffer_use_malloc ? buffer : NULL, - newbuflen); - if (newbuf == NULL) - { - *errnop = ENOMEM; - status = NSS_STATUS_TRYAGAIN; - goto out; - } - buffer = newbuf; - buflen = newbuflen; - buffer_use_malloc = true; + *errnop = ENOMEM; + status = NSS_STATUS_TRYAGAIN; + goto out; } - else - buffer = extend_alloca (buffer, buflen, newbuflen); /* Reread current line, the parser has clobbered it. */ fsetpos (stream, &pos); continue; @@ -132,8 +121,7 @@ _nss_files_initgroups_dyn (const char *user, gid_t group, long int *start, out: /* Free memory. */ - if (buffer_use_malloc) - free (buffer); + scratch_buffer_free (&tmpbuf); free (line); fclose (stream); diff --git a/posix/wordexp.c b/posix/wordexp.c index 0b669a8f5e05ed15..7548e0329fdeafaa 100644 --- a/posix/wordexp.c +++ b/posix/wordexp.c @@ -17,7 +17,6 @@ License along with the GNU C Library; if not, see . */ -#include #include #include #include @@ -41,6 +40,7 @@ #include #include #include +#include #include #include <_itoa.h> @@ -299,12 +299,7 @@ parse_tilde (char **word, size_t *word_length, size_t *max_length, if (i == 1 + *offset) { /* Tilde appears on its own */ - uid_t uid; - struct passwd pwd, *tpwd; - int buflen = 1000; char* home; - char* buffer; - int result; /* POSIX.2 says ~ expands to $HOME and if HOME is unset the results are unspecified. We do a lookup on the uid if @@ -319,25 +314,38 @@ parse_tilde (char **word, size_t *word_length, size_t *max_length, } else { - uid = __getuid (); - buffer = __alloca (buflen); - - while ((result = __getpwuid_r (uid, &pwd, buffer, buflen, &tpwd)) != 0 + struct passwd pwd, *tpwd; + uid_t uid = __getuid (); + int result; + struct scratch_buffer tmpbuf; + scratch_buffer_init (&tmpbuf); + + while ((result = __getpwuid_r (uid, &pwd, + tmpbuf.data, tmpbuf.length, + &tpwd)) != 0 && errno == ERANGE) - buffer = extend_alloca (buffer, buflen, buflen + 1000); + if (!scratch_buffer_grow (&tmpbuf)) + return WRDE_NOSPACE; if (result == 0 && tpwd != NULL && pwd.pw_dir != NULL) { *word = w_addstr (*word, word_length, max_length, pwd.pw_dir); if (*word == NULL) - return WRDE_NOSPACE; + { + scratch_buffer_free (&tmpbuf); + return WRDE_NOSPACE; + } } else { *word = w_addchar (*word, word_length, max_length, '~'); if (*word == NULL) - return WRDE_NOSPACE; + { + scratch_buffer_free (&tmpbuf); + return WRDE_NOSPACE; + } } + scratch_buffer_free (&tmpbuf); } } else @@ -345,13 +353,15 @@ parse_tilde (char **word, size_t *word_length, size_t *max_length, /* Look up user name in database to get home directory */ char *user = strndupa (&words[1 + *offset], i - (1 + *offset)); struct passwd pwd, *tpwd; - int buflen = 1000; - char* buffer = __alloca (buflen); int result; + struct scratch_buffer tmpbuf; + scratch_buffer_init (&tmpbuf); - while ((result = __getpwnam_r (user, &pwd, buffer, buflen, &tpwd)) != 0 + while ((result = __getpwnam_r (user, &pwd, tmpbuf.data, tmpbuf.length, + &tpwd)) != 0 && errno == ERANGE) - buffer = extend_alloca (buffer, buflen, buflen + 1000); + if (!scratch_buffer_grow (&tmpbuf)) + return WRDE_NOSPACE; if (result == 0 && tpwd != NULL && pwd.pw_dir) *word = w_addstr (*word, word_length, max_length, pwd.pw_dir); @@ -363,6 +373,8 @@ parse_tilde (char **word, size_t *word_length, size_t *max_length, *word = w_addstr (*word, word_length, max_length, user); } + scratch_buffer_free (&tmpbuf); + *offset = i - 1; } return *word ? 0 : WRDE_NOSPACE; diff --git a/sysdeps/unix/sysv/linux/gethostid.c b/sysdeps/unix/sysv/linux/gethostid.c index 73c56e57e5aa4422..ec1c8c5bfcd57077 100644 --- a/sysdeps/unix/sysv/linux/gethostid.c +++ b/sysdeps/unix/sysv/linux/gethostid.c @@ -63,13 +63,12 @@ sethostid (long int id) # include # include # include +# include long int gethostid (void) { char hostname[MAXHOSTNAMELEN + 1]; - size_t buflen; - char *buffer; struct hostent hostbuf, *hp; int32_t id; struct in_addr in; @@ -94,23 +93,26 @@ gethostid (void) /* This also fails. Return and arbitrary value. */ return 0; - buflen = 1024; - buffer = __alloca (buflen); + struct scratch_buffer tmpbuf; + scratch_buffer_init (&tmpbuf); /* To get the IP address we need to know the host name. */ - while (__gethostbyname_r (hostname, &hostbuf, buffer, buflen, &hp, &herr) - != 0 + while (__gethostbyname_r (hostname, &hostbuf, + tmpbuf.data, tmpbuf.length, &hp, &herr) != 0 || hp == NULL) if (herr != NETDB_INTERNAL || errno != ERANGE) - return 0; + { + scratch_buffer_free (&tmpbuf); + return 0; + } else - /* Enlarge buffer. */ - buffer = extend_alloca (buffer, buflen, 2 * buflen); + if (!scratch_buffer_grow (&tmpbuf)) + return 0; in.s_addr = 0; memcpy (&in, hp->h_addr, (int) sizeof (in) < hp->h_length ? (int) sizeof (in) : hp->h_length); - + scratch_buffer_free (&tmpbuf); /* For the return value to be not exactly the IP address we do some bit fiddling. */ return (int32_t) (in.s_addr << 16 | in.s_addr >> 16);