From 682d9da486e4cbfd717edb8d95cd388b5d9227b2 Mon Sep 17 00:00:00 2001 From: Bruno Wolff III Date: Thu, 23 Sep 2021 09:06:48 -0500 Subject: [PATCH] Include a couple of important upstream fixes There are two notable fixes scheduled for the next release that we should get in the package now. cifs.upcall: fix regression in kerberos mount mount.cifs: fix crash when mount point does not exist --- cifs-utils.spec | 13 +- mount-crash-fix.patch | 40 ++++ upcall-fix.patch | 429 ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 481 insertions(+), 1 deletion(-) create mode 100644 mount-crash-fix.patch create mode 100644 upcall-fix.patch diff --git a/cifs-utils.spec b/cifs-utils.spec index 140eeca..289822b 100644 --- a/cifs-utils.spec +++ b/cifs-utils.spec @@ -3,7 +3,7 @@ Name: cifs-utils Version: 6.13 -Release: 1%{pre_release}%{?dist} +Release: 2%{pre_release}%{?dist} Summary: Utilities for mounting and managing CIFS mounts License: GPLv3 @@ -21,6 +21,12 @@ Requires(preun): /usr/sbin/alternatives Recommends: %{name}-info%{?_isa} = %{version}-%{release} Source0: https://download.samba.org/pub/linux-cifs/cifs-utils/%{name}-%{version}.tar.bz2 +# Fix for upcall cap issue +# https://github.com/piastry/cifs-utils/commit/7f9711dd902a239c499682015d708f73ec884af2 +Patch0: upcall-fix.patch +# Fix for mount crash +# https://github.com/piastry/cifs-utils/commit/9ad46fc480818e48868ba841a8a1eed9a74e7294 +Patch1: mount-crash-fix.patch %description The SMB/CIFS protocol is a standard file sharing protocol widely deployed @@ -124,6 +130,11 @@ about CIFS mount. %{_mandir}/man1/smbinfo.* %changelog +* Thu Sep 23 2021 Bruno Wolff III - 6.13-2 +- Pull in a couple of upstream fixes slotted for the next release +- fix regression in kerberos mount +- fix crash when mount point does not exist + * Wed Sep 22 2021 Bruno Wolff III - 6.13-1 - Fix for CVE-2021-20208: cifs.upcall kerberos auth leak in container - get/setcifsacl tools are improved to support changing owner, group and SACLs diff --git a/mount-crash-fix.patch b/mount-crash-fix.patch new file mode 100644 index 0000000..de96d4f --- /dev/null +++ b/mount-crash-fix.patch @@ -0,0 +1,40 @@ +diff --git a/mount.cifs.c b/mount.cifs.c +index 7f898bbd215a..84274c98ddf5 100644 +--- a/mount.cifs.c ++++ b/mount.cifs.c +@@ -1996,9 +1996,9 @@ acquire_mountpoint(char **mountpointp) + */ + realuid = getuid(); + if (realuid == 0) { +- dacrc = toggle_dac_capability(0, 1); +- if (dacrc) +- return dacrc; ++ rc = toggle_dac_capability(0, 1); ++ if (rc) ++ goto out; + } else { + oldfsuid = setfsuid(realuid); + oldfsgid = setfsgid(getgid()); +@@ -2019,7 +2019,6 @@ acquire_mountpoint(char **mountpointp) + rc = EX_SYSERR; + } + +- *mountpointp = mountpoint; + restore_privs: + if (realuid == 0) { + dacrc = toggle_dac_capability(0, 0); +@@ -2030,9 +2029,13 @@ restore_privs: + gid_t __attribute__((unused)) gignore = setfsgid(oldfsgid); + } + +- if (rc) ++out: ++ if (rc) { + free(mountpoint); ++ mountpoint = NULL; ++ } + ++ *mountpointp = mountpoint; + return rc; + } + diff --git a/upcall-fix.patch b/upcall-fix.patch new file mode 100644 index 0000000..6ab2c10 --- /dev/null +++ b/upcall-fix.patch @@ -0,0 +1,429 @@ +diff --git a/cifs.upcall.c b/cifs.upcall.c +index e4139349fea7..ad0430157958 100644 +--- a/cifs.upcall.c ++++ b/cifs.upcall.c +@@ -52,6 +52,9 @@ + #include + #include + #include ++#include ++#include ++#include + + #include "data_blob.h" + #include "spnego.h" +@@ -787,6 +790,25 @@ handle_krb5_mech(const char *oid, const char *host, DATA_BLOB * secblob, + return retval; + } + ++ ++ ++struct decoded_args { ++ int ver; ++ char hostname[NI_MAXHOST + 1]; ++ char ip[NI_MAXHOST + 1]; ++ ++/* Max user name length. */ ++#define MAX_USERNAME_SIZE 256 ++ char username[MAX_USERNAME_SIZE + 1]; ++ ++ uid_t uid; ++ uid_t creduid; ++ pid_t pid; ++ sectype_t sec; ++ ++/* ++ * Flags to keep track of what was provided ++ */ + #define DKD_HAVE_HOSTNAME 0x1 + #define DKD_HAVE_VERSION 0x2 + #define DKD_HAVE_SEC 0x4 +@@ -796,23 +818,13 @@ handle_krb5_mech(const char *oid, const char *host, DATA_BLOB * secblob, + #define DKD_HAVE_CREDUID 0x40 + #define DKD_HAVE_USERNAME 0x80 + #define DKD_MUSTHAVE_SET (DKD_HAVE_HOSTNAME|DKD_HAVE_VERSION|DKD_HAVE_SEC) +- +-struct decoded_args { +- int ver; +- char *hostname; +- char *ip; +- char *username; +- uid_t uid; +- uid_t creduid; +- pid_t pid; +- sectype_t sec; ++ int have; + }; + + static unsigned int +-decode_key_description(const char *desc, struct decoded_args *arg) ++__decode_key_description(const char *desc, struct decoded_args *arg) + { +- int len; +- int retval = 0; ++ size_t len; + char *pos; + const char *tkn = desc; + +@@ -826,13 +838,13 @@ decode_key_description(const char *desc, struct decoded_args *arg) + len = pos - tkn; + + len -= 5; +- free(arg->hostname); +- arg->hostname = strndup(tkn + 5, len); +- if (arg->hostname == NULL) { +- syslog(LOG_ERR, "Unable to allocate memory"); ++ if (len > sizeof(arg->hostname)-1) { ++ syslog(LOG_ERR, "host= value too long for buffer"); + return 1; + } +- retval |= DKD_HAVE_HOSTNAME; ++ memset(arg->hostname, 0, sizeof(arg->hostname)); ++ strncpy(arg->hostname, tkn + 5, len); ++ arg->have |= DKD_HAVE_HOSTNAME; + syslog(LOG_DEBUG, "host=%s", arg->hostname); + } else if (!strncmp(tkn, "ip4=", 4) || !strncmp(tkn, "ip6=", 4)) { + if (pos == NULL) +@@ -841,13 +853,13 @@ decode_key_description(const char *desc, struct decoded_args *arg) + len = pos - tkn; + + len -= 4; +- free(arg->ip); +- arg->ip = strndup(tkn + 4, len); +- if (arg->ip == NULL) { +- syslog(LOG_ERR, "Unable to allocate memory"); ++ if (len > sizeof(arg->ip)-1) { ++ syslog(LOG_ERR, "ip[46]= value too long for buffer"); + return 1; + } +- retval |= DKD_HAVE_IP; ++ memset(arg->ip, 0, sizeof(arg->ip)); ++ strncpy(arg->ip, tkn + 4, len); ++ arg->have |= DKD_HAVE_IP; + syslog(LOG_DEBUG, "ip=%s", arg->ip); + } else if (strncmp(tkn, "user=", 5) == 0) { + if (pos == NULL) +@@ -856,13 +868,13 @@ decode_key_description(const char *desc, struct decoded_args *arg) + len = pos - tkn; + + len -= 5; +- free(arg->username); +- arg->username = strndup(tkn + 5, len); +- if (arg->username == NULL) { +- syslog(LOG_ERR, "Unable to allocate memory"); ++ if (len > sizeof(arg->username)-1) { ++ syslog(LOG_ERR, "user= value too long for buffer"); + return 1; + } +- retval |= DKD_HAVE_USERNAME; ++ memset(arg->username, 0, sizeof(arg->username)); ++ strncpy(arg->username, tkn + 5, len); ++ arg->have |= DKD_HAVE_USERNAME; + syslog(LOG_DEBUG, "user=%s", arg->username); + } else if (strncmp(tkn, "pid=", 4) == 0) { + errno = 0; +@@ -873,13 +885,13 @@ decode_key_description(const char *desc, struct decoded_args *arg) + return 1; + } + syslog(LOG_DEBUG, "pid=%u", arg->pid); +- retval |= DKD_HAVE_PID; ++ arg->have |= DKD_HAVE_PID; + } else if (strncmp(tkn, "sec=", 4) == 0) { + if (strncmp(tkn + 4, "krb5", 4) == 0) { +- retval |= DKD_HAVE_SEC; ++ arg->have |= DKD_HAVE_SEC; + arg->sec = KRB5; + } else if (strncmp(tkn + 4, "mskrb5", 6) == 0) { +- retval |= DKD_HAVE_SEC; ++ arg->have |= DKD_HAVE_SEC; + arg->sec = MS_KRB5; + } + syslog(LOG_DEBUG, "sec=%d", arg->sec); +@@ -891,7 +903,7 @@ decode_key_description(const char *desc, struct decoded_args *arg) + strerror(errno)); + return 1; + } +- retval |= DKD_HAVE_UID; ++ arg->have |= DKD_HAVE_UID; + syslog(LOG_DEBUG, "uid=%u", arg->uid); + } else if (strncmp(tkn, "creduid=", 8) == 0) { + errno = 0; +@@ -901,7 +913,7 @@ decode_key_description(const char *desc, struct decoded_args *arg) + strerror(errno)); + return 1; + } +- retval |= DKD_HAVE_CREDUID; ++ arg->have |= DKD_HAVE_CREDUID; + syslog(LOG_DEBUG, "creduid=%u", arg->creduid); + } else if (strncmp(tkn, "ver=", 4) == 0) { /* if version */ + errno = 0; +@@ -911,14 +923,56 @@ decode_key_description(const char *desc, struct decoded_args *arg) + strerror(errno)); + return 1; + } +- retval |= DKD_HAVE_VERSION; ++ arg->have |= DKD_HAVE_VERSION; + syslog(LOG_DEBUG, "ver=%d", arg->ver); + } + if (pos == NULL) + break; + tkn = pos + 1; + } while (tkn); +- return retval; ++ return 0; ++} ++ ++static unsigned int ++decode_key_description(const char *desc, struct decoded_args **arg) ++{ ++ pid_t pid; ++ pid_t rc; ++ int status; ++ ++ /* ++ * Do all the decoding/string processing in a child process ++ * with low privileges. ++ */ ++ ++ *arg = mmap(NULL, sizeof(struct decoded_args), PROT_READ | PROT_WRITE, ++ MAP_ANONYMOUS | MAP_SHARED, -1, 0); ++ if (*arg == MAP_FAILED) { ++ syslog(LOG_ERR, "%s: mmap failed: %s", __func__, strerror(errno)); ++ return -1; ++ } ++ ++ pid = fork(); ++ if (pid < 0) { ++ syslog(LOG_ERR, "%s: fork failed: %s", __func__, strerror(errno)); ++ munmap(*arg, sizeof(struct decoded_args)); ++ *arg = NULL; ++ return -1; ++ } ++ if (pid == 0) { ++ /* do the parsing in child */ ++ drop_all_capabilities(); ++ exit(__decode_key_description(desc, *arg)); ++ } ++ ++ rc = waitpid(pid, &status, 0); ++ if (rc < 0 || !WIFEXITED(status) || WEXITSTATUS(status) != 0) { ++ munmap(*arg, sizeof(struct decoded_args)); ++ *arg = NULL; ++ return 1; ++ } ++ ++ return 0; + } + + static int setup_key(const key_serial_t key, const void *data, size_t datalen) +@@ -1098,7 +1152,7 @@ int main(const int argc, char *const argv[]) + bool try_dns = false, legacy_uid = false , env_probe = true; + char *buf; + char hostbuf[NI_MAXHOST], *host; +- struct decoded_args arg; ++ struct decoded_args *arg = NULL; + const char *oid; + uid_t uid; + char *keytab_name = NULL; +@@ -1109,7 +1163,6 @@ int main(const int argc, char *const argv[]) + const char *key_descr = NULL; + + hostbuf[0] = '\0'; +- memset(&arg, 0, sizeof(arg)); + + openlog(prog, 0, LOG_DAEMON); + +@@ -1150,9 +1203,6 @@ int main(const int argc, char *const argv[]) + } + } + +- if (trim_capabilities(env_probe)) +- goto out; +- + /* is there a key? */ + if (argc <= optind) { + usage(); +@@ -1178,6 +1228,10 @@ int main(const int argc, char *const argv[]) + + syslog(LOG_DEBUG, "key description: %s", buf); + ++ /* ++ * If we are requested a simple DNS query, do it and exit ++ */ ++ + if (strncmp(buf, "cifs.resolver", sizeof("cifs.resolver") - 1) == 0) + key_descr = ".cifs.resolver"; + else if (strncmp(buf, "dns_resolver", sizeof("dns_resolver") - 1) == 0) +@@ -1187,33 +1241,42 @@ int main(const int argc, char *const argv[]) + goto out; + } + +- have = decode_key_description(buf, &arg); ++ /* ++ * Otherwise, it's a spnego key request ++ */ ++ ++ rc = decode_key_description(buf, &arg); + free(buf); +- if ((have & DKD_MUSTHAVE_SET) != DKD_MUSTHAVE_SET) { ++ if (rc) { ++ syslog(LOG_ERR, "failed to decode key description"); ++ goto out; ++ } ++ ++ if ((arg->have & DKD_MUSTHAVE_SET) != DKD_MUSTHAVE_SET) { + syslog(LOG_ERR, "unable to get necessary params from key " + "description (0x%x)", have); + rc = 1; + goto out; + } + +- if (arg.ver > CIFS_SPNEGO_UPCALL_VERSION) { ++ if (arg->ver > CIFS_SPNEGO_UPCALL_VERSION) { + syslog(LOG_ERR, "incompatible kernel upcall version: 0x%x", +- arg.ver); ++ arg->ver); + rc = 1; + goto out; + } + +- if (strlen(arg.hostname) >= NI_MAXHOST) { ++ if (strlen(arg->hostname) >= NI_MAXHOST) { + syslog(LOG_ERR, "hostname provided by kernel is too long"); + rc = 1; + goto out; + + } + +- if (!legacy_uid && (have & DKD_HAVE_CREDUID)) +- uid = arg.creduid; +- else if (have & DKD_HAVE_UID) +- uid = arg.uid; ++ if (!legacy_uid && (arg->have & DKD_HAVE_CREDUID)) ++ uid = arg->creduid; ++ else if (arg->have & DKD_HAVE_UID) ++ uid = arg->uid; + else { + /* no uid= or creduid= parm -- something is wrong */ + syslog(LOG_ERR, "No uid= or creduid= parm specified"); +@@ -1221,6 +1284,21 @@ int main(const int argc, char *const argv[]) + goto out; + } + ++ /* ++ * Change to the process's namespace. This means that things will work ++ * acceptably in containers, because we'll be looking at the correct ++ * filesystem and have the correct network configuration. ++ */ ++ rc = switch_to_process_ns(arg->pid); ++ if (rc == -1) { ++ syslog(LOG_ERR, "unable to switch to process namespace: %s", strerror(errno)); ++ rc = 1; ++ goto out; ++ } ++ ++ if (trim_capabilities(env_probe)) ++ goto out; ++ + /* + * The kernel doesn't pass down the gid, so we resort here to scraping + * one out of the passwd nss db. Note that this might not reflect the +@@ -1266,20 +1344,7 @@ int main(const int argc, char *const argv[]) + * look at the environ file. + */ + env_cachename = +- get_cachename_from_process_env(env_probe ? arg.pid : 0); +- +- /* +- * Change to the process's namespace. This means that things will work +- * acceptably in containers, because we'll be looking at the correct +- * filesystem and have the correct network configuration. +- */ +- rc = switch_to_process_ns(arg.pid); +- if (rc == -1) { +- syslog(LOG_ERR, "unable to switch to process namespace: %s", +- strerror(errno)); +- rc = 1; +- goto out; +- } ++ get_cachename_from_process_env(env_probe ? arg->pid : 0); + + rc = setuid(uid); + if (rc == -1) { +@@ -1301,18 +1366,18 @@ int main(const int argc, char *const argv[]) + + ccache = get_existing_cc(env_cachename); + /* Couldn't find credcache? Try to use keytab */ +- if (ccache == NULL && arg.username != NULL) +- ccache = init_cc_from_keytab(keytab_name, arg.username); ++ if (ccache == NULL && arg->username[0] != '\0') ++ ccache = init_cc_from_keytab(keytab_name, arg->username); + + if (ccache == NULL) { + rc = 1; + goto out; + } + +- host = arg.hostname; ++ host = arg->hostname; + + // do mech specific authorization +- switch (arg.sec) { ++ switch (arg->sec) { + case MS_KRB5: + case KRB5: + /* +@@ -1328,7 +1393,7 @@ int main(const int argc, char *const argv[]) + * TRY only: + * cifs/bar.example.com@REALM + */ +- if (arg.sec == MS_KRB5) ++ if (arg->sec == MS_KRB5) + oid = OID_KERBEROS5_OLD; + else + oid = OID_KERBEROS5; +@@ -1385,10 +1450,10 @@ retry_new_hostname: + break; + } + +- if (!try_dns || !(have & DKD_HAVE_IP)) ++ if (!try_dns || !(arg->have & DKD_HAVE_IP)) + break; + +- rc = ip_to_fqdn(arg.ip, hostbuf, sizeof(hostbuf)); ++ rc = ip_to_fqdn(arg->ip, hostbuf, sizeof(hostbuf)); + if (rc) + break; + +@@ -1396,7 +1461,7 @@ retry_new_hostname: + host = hostbuf; + goto retry_new_hostname; + default: +- syslog(LOG_ERR, "sectype: %d is not implemented", arg.sec); ++ syslog(LOG_ERR, "sectype: %d is not implemented", arg->sec); + rc = 1; + break; + } +@@ -1414,7 +1479,7 @@ retry_new_hostname: + rc = 1; + goto out; + } +- keydata->version = arg.ver; ++ keydata->version = arg->ver; + keydata->flags = 0; + keydata->sesskey_len = sess_key.length; + keydata->secblob_len = secblob.length; +@@ -1440,11 +1505,10 @@ out: + krb5_cc_close(context, ccache); + if (context) + krb5_free_context(context); +- free(arg.hostname); +- free(arg.ip); +- free(arg.username); + free(keydata); + free(env_cachename); ++ if (arg) ++ munmap(arg, sizeof(*arg)); + syslog(LOG_DEBUG, "Exit status %ld", rc); + return rc; + }