From ec99e297ec21a794af038ae0b8ad9eae6a5b7a54 Mon Sep 17 00:00:00 2001 From: Patsy Griffin Date: Mon, 22 Jun 2026 06:53:56 -0400 Subject: [PATCH] CVE-2026-5450: Fix buffer overflow in scanf (RHEL-172710) Resolves: RHEL-172710 --- glibc-RHEL-172710-1.patch | 126 +++++++++++ glibc-RHEL-172710-2.patch | 80 +++++++ glibc-RHEL-172710-3.patch | 457 ++++++++++++++++++++++++++++++++++++++ glibc-RHEL-172710-4.patch | 193 ++++++++++++++++ 4 files changed, 856 insertions(+) create mode 100644 glibc-RHEL-172710-1.patch create mode 100644 glibc-RHEL-172710-2.patch create mode 100644 glibc-RHEL-172710-3.patch create mode 100644 glibc-RHEL-172710-4.patch diff --git a/glibc-RHEL-172710-1.patch b/glibc-RHEL-172710-1.patch new file mode 100644 index 0000000..1bd6427 --- /dev/null +++ b/glibc-RHEL-172710-1.patch @@ -0,0 +1,126 @@ +commit 839898777226a3ed88c0859f25ffe712519b4ead +Author: Rocket Ma +Date: Fri Apr 17 23:48:41 2026 -0700 + + stdio-common: Fix buffer overflow in scanf %mc [BZ #34008] + + * stdio-common/vfscanf-internal.c: When enlarging allocated buffer with + format %mc or %mC, glibc allocates one byte less, leading to + user-controlled one byte overflow. This commit fixes BZ #34008, or + CVE-2026-5450. + + Reviewed-by: Carlos O'Donell + Signed-off-by: Rocket Ma + Reviewed-by: H.J. Lu + +Conflicts: + stdio-common/Makefile + (usual test differences) + +diff -Nrup a/stdio-common/Makefile b/stdio-common/Makefile +--- a/stdio-common/Makefile 2026-06-16 08:24:01.348860456 -0400 ++++ b/stdio-common/Makefile 2026-06-16 08:18:22.791126117 -0400 +@@ -290,6 +290,7 @@ tests := \ + tst-vfprintf-mbs-prec \ + tst-vfprintf-user-type \ + tst-vfprintf-width-prec-alloc \ ++ tst-vfscanf-bz34008 \ + tst-wc-printf \ + tstdiomisc \ + tstgetln \ +@@ -441,6 +442,9 @@ tst-printf-bz18872-ENV = MALLOC_TRACE=$( + tst-vfprintf-width-prec-ENV = \ + MALLOC_TRACE=$(objpfx)tst-vfprintf-width-prec.mtrace \ + LD_PRELOAD=$(common-objpfx)/malloc/libc_malloc_debug.so ++tst-vfscanf-bz34008-ENV = \ ++ MALLOC_CHECK_=3 \ ++ LD_PRELOAD=$(common-objpfx)/malloc/libc_malloc_debug.so + tst-printf-bz25691-ENV = \ + MALLOC_TRACE=$(objpfx)tst-printf-bz25691.mtrace \ + LD_PRELOAD=$(common-objpfx)/malloc/libc_malloc_debug.so +diff --git a/stdio-common/tst-vfscanf-bz34008.c b/stdio-common/tst-vfscanf-bz34008.c +new file mode 100644 +index 0000000000..48371c8a3d +--- /dev/null ++++ b/stdio-common/tst-vfscanf-bz34008.c +@@ -0,0 +1,48 @@ ++/* Regression test for vfscanf %Nmc out-of-bound write (BZ #34008) ++ Copyright (C) 2026 The GNU Toolchain Authors. ++ This file is part of the GNU C Library. ++ ++ The GNU C Library is free software; you can redistribute it and/or ++ modify it under the terms of the GNU Lesser General Public ++ License as published by the Free Software Foundation; either ++ version 2.1 of the License, or (at your option) any later version. ++ ++ The GNU C Library is distributed in the hope that it will be useful, ++ but WITHOUT ANY WARRANTY; without even the implied warranty of ++ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU ++ Lesser General Public License for more details. ++ ++ You should have received a copy of the GNU Lesser General Public ++ License along with the GNU C Library; if not, see ++ . */ ++ ++#include "malloc/mcheck.h" ++#include ++#include ++#include ++#include ++#include ++#include ++#include ++ ++#define WIDTH 0x410 ++#define SCANFSTR "%1040mc" ++static int ++do_test (void) ++{ ++ mcheck_pedantic (NULL); ++ char *input = malloc (WIDTH + 1); ++ TEST_VERIFY (input != NULL); ++ memset (input, 'A', WIDTH); ++ input[WIDTH] = '\0'; ++ ++ char *buf = NULL; ++ TEST_VERIFY (sscanf (input, SCANFSTR, &buf) != -1); ++ TEST_VERIFY (buf != NULL); ++ ++ free (buf); ++ free (input); ++ return 0; ++} ++ ++#include +diff --git a/stdio-common/vfscanf-internal.c b/stdio-common/vfscanf-internal.c +index 59fc8208aa..3d11ac261e 100644 +--- a/stdio-common/vfscanf-internal.c ++++ b/stdio-common/vfscanf-internal.c +@@ -855,8 +855,7 @@ __vfscanf_internal (FILE *s, const char *format, va_list argptr, + { + /* Enlarge the buffer. */ + size_t newsize +- = strsize +- + (strsize >= width ? width - 1 : strsize); ++ = strsize + (strsize >= width ? width : strsize); + + str = (char *) realloc (*strptr, newsize); + if (str == NULL) +@@ -929,7 +928,7 @@ __vfscanf_internal (FILE *s, const char *format, va_list argptr, + && wstr == (wchar_t *) *strptr + strsize) + { + size_t newsize +- = strsize + (strsize > width ? width - 1 : strsize); ++ = strsize + (strsize >= width ? width : strsize); + /* Enlarge the buffer. */ + wstr = (wchar_t *) realloc (*strptr, + newsize * sizeof (wchar_t)); +@@ -984,7 +983,7 @@ __vfscanf_internal (FILE *s, const char *format, va_list argptr, + && wstr == (wchar_t *) *strptr + strsize) + { + size_t newsize +- = strsize + (strsize > width ? width - 1 : strsize); ++ = strsize + (strsize >= width ? width : strsize); + /* Enlarge the buffer. */ + wstr = (wchar_t *) realloc (*strptr, + newsize * sizeof (wchar_t)); diff --git a/glibc-RHEL-172710-2.patch b/glibc-RHEL-172710-2.patch new file mode 100644 index 0000000..a334a8c --- /dev/null +++ b/glibc-RHEL-172710-2.patch @@ -0,0 +1,80 @@ +commit b866ef29773b22a1343ff9084374775114350b78 +Author: Maciej W. Rozycki +Date: Wed May 27 12:57:10 2026 -0400 + + support: Implement 'xfmemopen' for seamless 'fmemopen' use + + Add 'xfmemopen' wrapper for seamless 'fmemopen' use in tests, following + 'xfopen', 'xfclose', etc., and providing a standardized error reporting + facility. + + Reviewed-by: Florian Weimer + (cherry picked from commit fe709cc24578ecfd2ff5b07e10e3829fcb55075b) + + Reviewed-by: Carlos O'Donell + +Conflicts: + support/Makefile + (usual test differences) + support/xstdio.h + (adjust for downstream context difference) + +diff -Nrup a/support/Makefile b/support/Makefile +--- a/support/Makefile 2026-06-16 10:34:13.241874132 -0400 ++++ b/support/Makefile 2026-06-16 10:37:06.085172353 -0400 +@@ -135,6 +135,7 @@ libsupport-routines = \ + xfchmod \ + xfclose \ + xfdopendir \ ++ xfmemopen \ + xfopen \ + xfork \ + xfread \ +diff --git a/support/xfmemopen.c b/support/xfmemopen.c +new file mode 100644 +index 0000000000..f1dbc72c67 +--- /dev/null ++++ b/support/xfmemopen.c +@@ -0,0 +1,31 @@ ++/* fmemopen with error checking. ++ Copyright (C) 2025 Free Software Foundation, Inc. ++ This file is part of the GNU C Library. ++ ++ The GNU C Library is free software; you can redistribute it and/or ++ modify it under the terms of the GNU Lesser General Public ++ License as published by the Free Software Foundation; either ++ version 2.1 of the License, or (at your option) any later version. ++ ++ The GNU C Library is distributed in the hope that it will be useful, ++ but WITHOUT ANY WARRANTY; without even the implied warranty of ++ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU ++ Lesser General Public License for more details. ++ ++ You should have received a copy of the GNU Lesser General Public ++ License along with the GNU C Library; if not, see ++ . */ ++ ++#include ++ ++#include ++#include ++ ++FILE * ++xfmemopen (void *mem, size_t len, const char *mode) ++{ ++ FILE *fp = fmemopen (mem, len, mode); ++ if (fp == NULL) ++ FAIL_EXIT1 ("fmemopen (mode \"%s\"): %m", mode); ++ return fp; ++} +diff -Nrup a/support/xstdio.h b/support/xstdio.h +--- a/support/xstdio.h 2026-06-16 10:34:10.450856660 -0400 ++++ b/support/xstdio.h 2026-06-16 10:39:05.792825780 -0400 +@@ -26,6 +26,7 @@ __BEGIN_DECLS + + FILE *xfopen (const char *path, const char *mode); + void xfclose (FILE *); ++FILE *xfmemopen (void *mem, size_t len, const char *mode); + void xfread (void *ptr, size_t size, size_t nmemb, FILE *stream); + + /* Read a line from FP, using getline. *BUFFER must be NULL, or a diff --git a/glibc-RHEL-172710-3.patch b/glibc-RHEL-172710-3.patch new file mode 100644 index 0000000..6bfe8c5 --- /dev/null +++ b/glibc-RHEL-172710-3.patch @@ -0,0 +1,457 @@ +commit 97926e9017f3faeaacce9337f1288460f5e6ec7d +Author: Maciej W. Rozycki +Date: Wed May 27 12:57:10 2026 -0400 + + stdio-common: Reject insufficient character data in scanf [BZ #12701] + + Reject invalid formatted scanf character data with the 'c' conversion + where there is not enough input available to satisfy the field width + requested. It is required by ISO C that this conversion matches a + sequence of characters of exactly the number specified by the field + width and it is also already documented as such in our own manual: + + "It reads precisely the next N characters, and fails if it cannot get + that many." + + Currently a matching success is instead incorrectly produced where the + EOF condition is encountered before the required number of characters + has been retrieved, and the characters actually obtained are stored in + the buffer provided. + + Add test cases accordingly and remove placeholders from 'c' conversion + input data for the existing scanf tests. + + Reviewed-by: Adhemerval Zanella + + [This is a modified version of commit 2b16c76609, which tests for the + old behavior and only includes the test cases, for older branches + and downstream backports - DJ] + + Reviewed-by: Carlos O'Donell + +Conflicts: + localedata/Makefile + stdio-common/Makefile + (usual test differences) + +diff -Nrup a/localedata/Makefile b/localedata/Makefile +--- a/localedata/Makefile 2026-06-16 09:15:19.295653341 -0400 ++++ b/localedata/Makefile 2026-06-16 09:11:51.111414458 -0400 +@@ -160,6 +160,7 @@ tests = \ + bug-iconv-trans \ + bug-setlocale1 \ + bug-usesetlocale \ ++ tst-bz12701-lc \ + tst-c-utf8-consistency \ + tst-digits \ + tst-iconv-math-trans \ +diff --git a/localedata/tst-bz12701-lc.c b/localedata/tst-bz12701-lc.c +new file mode 100644 +index 0000000000..23c2ab7d2a +--- /dev/null ++++ b/localedata/tst-bz12701-lc.c +@@ -0,0 +1,218 @@ ++/* Verify scanf field width handling with the 'lc' conversion (BZ #12701). ++ Copyright (C) 2025-2026 Free Software Foundation, Inc. ++ This file is part of the GNU C Library. ++ ++ The GNU C Library is free software; you can redistribute it and/or ++ modify it under the terms of the GNU Lesser General Public ++ License as published by the Free Software Foundation; either ++ version 2.1 of the License, or (at your option) any later version. ++ ++ The GNU C Library is distributed in the hope that it will be useful, ++ but WITHOUT ANY WARRANTY; without even the implied warranty of ++ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU ++ Lesser General Public License for more details. ++ ++ You should have received a copy of the GNU Lesser General Public ++ License along with the GNU C Library; if not, see ++ . */ ++ ++#include ++#include ++#include ++#include ++#include ++ ++#include ++#include ++#include ++#include ++ ++/* Compare character-wise the initial part of the wide character object ++ pointed to by WS corresponding to wide characters obtained by the ++ conversion of first N bytes of the multibyte character object pointed ++ to by S. */ ++ ++static int ++tst_bz12701_lc_memcmp (const wchar_t *ds, const char *s, size_t n) ++{ ++ size_t nc = mbsnrtowcs (NULL, &s, n, 0, NULL); ++ ++ struct support_next_to_fault ntf; ++ ntf = support_next_to_fault_allocate (nc * sizeof (wchar_t)); ++ wchar_t *ss = (wchar_t *) ntf.buffer; ++ ++ mbsnrtowcs (ss, &s, n, nc, NULL); ++ int r = wmemcmp (ds, ss, nc); ++ ++ support_next_to_fault_free (&ntf); ++ ++ return r; ++} ++ ++/* Verify various aspects of field width handling, including the data ++ obtained, the number of bytes consumed, and the stream position. */ ++ ++static int ++do_test (void) ++{ ++ if (setlocale (LC_ALL, "pl_PL.UTF-8") == NULL) ++ FAIL_EXIT1 ("setlocale (LC_ALL, \"pl_PL.UTF-8\")"); ++ ++ /* Part of a tongue-twister in Polish, which says: ++ "On a rainy morning cuckoos and warblers, rather than starting ++ on earthworms, stuffed themselves fasted with the flesh of cress." */ ++ static const char s[126] = "Dżdżystym rankiem gżegżółki i piegże, " ++ "zamiast wziąć się za dżdżownice, " ++ "nażarły się na czczo miąższu rzeżuchy"; ++ ++ const char *sp = s; ++ size_t nc; ++ TEST_VERIFY_EXIT ((nc = mbsnrtowcs (NULL, &sp, sizeof (s), 0, NULL)) == 108); ++ ++ struct support_next_to_fault ntfo, ntfi; ++ ntfo = support_next_to_fault_allocate (nc * sizeof (wchar_t)); ++ ntfi = support_next_to_fault_allocate (sizeof (s)); ++ wchar_t *e = (wchar_t *) ntfo.buffer + nc; ++ char *b = ntfi.buffer; ++ ++ wchar_t *c; ++ FILE *f; ++ int ic; ++ int n; ++ int i; ++ ++ memcpy (ntfi.buffer, s, sizeof (s)); ++ ++ ic = i = 0; ++ f = xfmemopen (b, sizeof (s), "r"); ++ ++ c = e - 1; ++ TEST_VERIFY_EXIT (ftell (f) == i); ++ /* Avoid: "warning: zero width in gnu_scanf format [-Werror=format=]". */ ++ DIAG_PUSH_NEEDS_COMMENT; ++ DIAG_IGNORE_NEEDS_COMMENT (4.9, "-Wformat"); ++ TEST_VERIFY_EXIT (fscanf (f, "%0lc%n", c, &n) == 1); ++ DIAG_POP_NEEDS_COMMENT; ++ TEST_VERIFY_EXIT (n == 1); ++ TEST_VERIFY_EXIT (tst_bz12701_lc_memcmp (c, s + i, n) == 0); ++ ic += 1; ++ i += n; ++ ++ c = e - 1; ++ TEST_VERIFY_EXIT (ftell (f) == i); ++ TEST_VERIFY_EXIT (fscanf (f, "%lc%n", c, &n) == 1); ++ TEST_VERIFY_EXIT (n == 2); ++ TEST_VERIFY_EXIT (tst_bz12701_lc_memcmp (c, s + i, n) == 0); ++ ic += 1; ++ i += n; ++ ++ c = e - 1; ++ TEST_VERIFY_EXIT (ftell (f) == i); ++ TEST_VERIFY_EXIT (fscanf (f, "%1lc%n", c, &n) == 1); ++ TEST_VERIFY_EXIT (n == 1); ++ TEST_VERIFY_EXIT (tst_bz12701_lc_memcmp (c, s + i, n) == 0); ++ ic += 1; ++ i += n; ++ ++ c = e - 2; ++ TEST_VERIFY_EXIT (ftell (f) == i); ++ TEST_VERIFY_EXIT (fscanf (f, "%2lc%n", c, &n) == 1); ++ TEST_VERIFY_EXIT (n == 3); ++ TEST_VERIFY_EXIT (tst_bz12701_lc_memcmp (c, s + i, n) == 0); ++ ic += 2; ++ i += n; ++ ++ c = e - 4; ++ TEST_VERIFY_EXIT (ftell (f) == i); ++ TEST_VERIFY_EXIT (fscanf (f, "%4lc%n", c, &n) == 1); ++ TEST_VERIFY_EXIT (n == 4); ++ TEST_VERIFY_EXIT (tst_bz12701_lc_memcmp (c, s + i, n) == 0); ++ ic += 4; ++ i += n; ++ ++ c = e - 8; ++ TEST_VERIFY_EXIT (ftell (f) == i); ++ TEST_VERIFY_EXIT (fscanf (f, "%8lc%n", c, &n) == 1); ++ TEST_VERIFY_EXIT (n == 8); ++ TEST_VERIFY_EXIT (tst_bz12701_lc_memcmp (c, s + i, n) == 0); ++ ic += 8; ++ i += n; ++ ++ c = e - 16; ++ TEST_VERIFY_EXIT (ftell (f) == i); ++ TEST_VERIFY_EXIT (fscanf (f, "%16lc%n", c, &n) == 1); ++ TEST_VERIFY_EXIT (n == 20); ++ TEST_VERIFY_EXIT (tst_bz12701_lc_memcmp (c, s + i, n) == 0); ++ ic += 16; ++ i += n; ++ ++ c = e - 32; ++ TEST_VERIFY_EXIT (ftell (f) == i); ++ TEST_VERIFY_EXIT (fscanf (f, "%32lc%n", c, &n) == 1); ++ TEST_VERIFY_EXIT (n == 38); ++ TEST_VERIFY_EXIT (tst_bz12701_lc_memcmp (c, s + i, n) == 0); ++ ic += 32; ++ i += n; ++ ++ c = e - (nc - ic); ++ TEST_VERIFY_EXIT (ftell (f) == i); ++ TEST_COMPARE (fscanf (f, "%64lc%n", c, &n), 1); ++ TEST_COMPARE (n , 49); ++ TEST_VERIFY_EXIT (tst_bz12701_lc_memcmp (c, s + i, sizeof (s) - i) == 0); ++ ++ TEST_VERIFY_EXIT (ftell (f) == sizeof (s)); ++ TEST_VERIFY_EXIT (feof (f) != 0); ++ ++ xfclose (f); ++ ++ ic = i = 0; ++ f = xfmemopen (b, 3, "r"); ++ ++ c = e - 2; ++ TEST_VERIFY_EXIT (ftell (f) == i); ++ TEST_VERIFY_EXIT (fscanf (f, "%2lc%n", c, &n) == 1); ++ TEST_VERIFY_EXIT (n == 3); ++ TEST_VERIFY_EXIT (tst_bz12701_lc_memcmp (c, s + i, n) == 0); ++ ic += 2; ++ i += n; ++ ++ c = e - (nc - ic); ++ TEST_VERIFY_EXIT (feof (f) == 0); ++ TEST_VERIFY_EXIT (ftell (f) == i); ++ TEST_VERIFY_EXIT (fscanf (f, "%2lc%n", c, &n) == EOF); ++ TEST_VERIFY_EXIT (n == 3); ++ ++ TEST_VERIFY_EXIT (ftell (f) == 3); ++ TEST_VERIFY_EXIT (feof (f) != 0); ++ ++ xfclose (f); ++ ++ ic = i = 0; ++ f = xfmemopen (b, 3, "r"); ++ ++ c = e - 1; ++ TEST_VERIFY_EXIT (ftell (f) == i); ++ TEST_VERIFY_EXIT (fscanf (f, "%lc%n", c, &n) == 1); ++ TEST_VERIFY_EXIT (n == 1); ++ TEST_VERIFY_EXIT (tst_bz12701_lc_memcmp (c, s + i, n) == 0); ++ ic += 1; ++ i += n; ++ ++ c = e - (nc - ic); ++ TEST_VERIFY_EXIT (ftell (f) == i); ++ TEST_VERIFY_EXIT (fscanf (f, "%2lc%n", c, &n) == 1); ++ TEST_VERIFY_EXIT (n == 2); ++ TEST_VERIFY_EXIT (tst_bz12701_lc_memcmp (c, s + i, 3 - i) == 0); ++ ++ TEST_VERIFY_EXIT (ftell (f) == 3); ++ TEST_VERIFY_EXIT (feof (f) != 0); ++ ++ xfclose (f); ++ ++ support_next_to_fault_free (&ntfi); ++ support_next_to_fault_free (&ntfo); ++ ++ return 0; ++} ++ ++#include +diff -Nrup a/stdio-common/Makefile b/stdio-common/Makefile +--- a/stdio-common/Makefile 2026-06-16 09:15:19.320447732 -0400 ++++ b/stdio-common/Makefile 2026-06-16 09:14:09.814624522 -0400 +@@ -217,6 +217,7 @@ tests := \ + tllformat \ + tst-bz11319 \ + tst-bz11319-fortify2 \ ++ tst-bz12701-c \ + tst-cookie \ + tst-fclose-devzero \ + tst-fclose-offset \ +diff --git a/stdio-common/tst-bz12701-c.c b/stdio-common/tst-bz12701-c.c +new file mode 100644 +index 0000000000..4f3616fbfd +--- /dev/null ++++ b/stdio-common/tst-bz12701-c.c +@@ -0,0 +1,169 @@ ++/* Verify scanf field width handling with the 'c' conversion (BZ #12701). ++ Copyright (C) 2025-2026 Free Software Foundation, Inc. ++ This file is part of the GNU C Library. ++ ++ The GNU C Library is free software; you can redistribute it and/or ++ modify it under the terms of the GNU Lesser General Public ++ License as published by the Free Software Foundation; either ++ version 2.1 of the License, or (at your option) any later version. ++ ++ The GNU C Library is distributed in the hope that it will be useful, ++ but WITHOUT ANY WARRANTY; without even the implied warranty of ++ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU ++ Lesser General Public License for more details. ++ ++ You should have received a copy of the GNU Lesser General Public ++ License along with the GNU C Library; if not, see ++ . */ ++ ++#include ++#include ++ ++#include ++#include ++#include ++#include ++ ++/* Verify various aspects of field width handling, including the data ++ obtained, the number of bytes consumed, and the stream position. */ ++ ++static int ++do_test (void) ++{ ++ static const char s[43] = "The quick brown fox jumps over the lazy dog"; ++ struct support_next_to_fault ntfo, ntfi; ++ ntfo = support_next_to_fault_allocate (sizeof (s)); ++ ntfi = support_next_to_fault_allocate (sizeof (s)); ++ char *e = ntfo.buffer + sizeof (s); ++ char *b = ntfi.buffer; ++ ++ char *c; ++ FILE *f; ++ int n; ++ int i; ++ ++ memcpy (ntfi.buffer, s, sizeof (s)); ++ ++ i = 0; ++ f = xfmemopen (b, sizeof (s), "r"); ++ ++ c = e - 1; ++ TEST_VERIFY_EXIT (ftell (f) == i); ++ /* Avoid: "warning: zero width in gnu_scanf format [-Werror=format=]". */ ++ DIAG_PUSH_NEEDS_COMMENT; ++ DIAG_IGNORE_NEEDS_COMMENT (4.9, "-Wformat"); ++ TEST_VERIFY_EXIT (fscanf (f, "%0c%n", c, &n) == 1); ++ DIAG_POP_NEEDS_COMMENT; ++ TEST_VERIFY_EXIT (n == 1); ++ TEST_VERIFY_EXIT (memcmp (c, s + i, n) == 0); ++ i += n; ++ ++ c = e - 1; ++ TEST_VERIFY_EXIT (ftell (f) == i); ++ TEST_VERIFY_EXIT (fscanf (f, "%c%n", c, &n) == 1); ++ TEST_VERIFY_EXIT (n == 1); ++ TEST_VERIFY_EXIT (memcmp (c, s + i, n) == 0); ++ i += n; ++ ++ c = e - 1; ++ TEST_VERIFY_EXIT (ftell (f) == i); ++ TEST_VERIFY_EXIT (fscanf (f, "%1c%n", c, &n) == 1); ++ TEST_VERIFY_EXIT (n == 1); ++ TEST_VERIFY_EXIT (memcmp (c, s + i, n) == 0); ++ i += n; ++ ++ c = e - 2; ++ TEST_VERIFY_EXIT (ftell (f) == i); ++ TEST_VERIFY_EXIT (fscanf (f, "%2c%n", c, &n) == 1); ++ TEST_VERIFY_EXIT (n == 2); ++ TEST_VERIFY_EXIT (memcmp (c, s + i, n) == 0); ++ i += n; ++ ++ c = e - 4; ++ TEST_VERIFY_EXIT (ftell (f) == i); ++ TEST_VERIFY_EXIT (fscanf (f, "%4c%n", c, &n) == 1); ++ TEST_VERIFY_EXIT (n == 4); ++ TEST_VERIFY_EXIT (memcmp (c, s + i, n) == 0); ++ i += n; ++ ++ c = e - 8; ++ TEST_VERIFY_EXIT (ftell (f) == i); ++ TEST_VERIFY_EXIT (fscanf (f, "%8c%n", c, &n) == 1); ++ TEST_VERIFY_EXIT (n == 8); ++ TEST_VERIFY_EXIT (memcmp (c, s + i, n) == 0); ++ i += n; ++ ++ c = e - 16; ++ TEST_VERIFY_EXIT (ftell (f) == i); ++ TEST_VERIFY_EXIT (fscanf (f, "%16c%n", c, &n) == 1); ++ TEST_VERIFY_EXIT (n == 16); ++ TEST_VERIFY_EXIT (memcmp (c, s + i, n) == 0); ++ i += n; ++ ++ c = e - (sizeof (s) - i); ++ TEST_VERIFY_EXIT (ftell (f) == i); ++ TEST_VERIFY_EXIT (fscanf (f, "%32c%n", c, &n) == 1); ++ TEST_VERIFY_EXIT (n == 10); ++ TEST_VERIFY_EXIT (memcmp (c, s + i, sizeof (s) - i) == 0); ++ ++ TEST_VERIFY_EXIT (ftell (f) == sizeof (s)); ++ TEST_VERIFY_EXIT (feof (f) != 0); ++ ++ xfclose (f); ++ ++ i = 0; ++ f = xfmemopen (b, 3, "r"); ++ ++ c = e - 1; ++ TEST_VERIFY_EXIT (ftell (f) == i); ++ TEST_VERIFY_EXIT (fscanf (f, "%c%n", c, &n) == 1); ++ TEST_VERIFY_EXIT (n == 1); ++ TEST_VERIFY_EXIT (memcmp (c, s + i, n) == 0); ++ i += n; ++ ++ c = e - 2; ++ TEST_VERIFY_EXIT (ftell (f) == i); ++ TEST_VERIFY_EXIT (fscanf (f, "%2c%n", c, &n) == 1); ++ TEST_VERIFY_EXIT (n == 2); ++ TEST_VERIFY_EXIT (memcmp (c, s + i, n) == 0); ++ i += n; ++ ++ c = e - (3 - i); ++ TEST_VERIFY_EXIT (feof (f) == 0); ++ TEST_VERIFY_EXIT (ftell (f) == i); ++ TEST_VERIFY_EXIT (fscanf (f, "%2c%n", c, &n) == EOF); ++ TEST_VERIFY_EXIT (n == 2); ++ ++ TEST_VERIFY_EXIT (ftell (f) == i); ++ TEST_VERIFY_EXIT (feof (f) != 0); ++ ++ xfclose (f); ++ ++ i = 0; ++ f = xfmemopen (b, 3, "r"); ++ ++ c = e - 2; ++ TEST_VERIFY_EXIT (ftell (f) == i); ++ TEST_VERIFY_EXIT (fscanf (f, "%2c%n", c, &n) == 1); ++ TEST_VERIFY_EXIT (n == 2); ++ TEST_VERIFY_EXIT (memcmp (c, s + i, n) == 0); ++ i += n; ++ ++ c = e - (3 - i); ++ TEST_VERIFY_EXIT (ftell (f) == i); ++ TEST_VERIFY_EXIT (fscanf (f, "%2c%n", c, &n) == 1); ++ TEST_VERIFY_EXIT (n == 1); ++ TEST_VERIFY_EXIT (memcmp (c, s + i, 3 - i) == 0); ++ ++ TEST_VERIFY_EXIT (ftell (f) == 3); ++ TEST_VERIFY_EXIT (feof (f) != 0); ++ ++ xfclose (f); ++ ++ support_next_to_fault_free (&ntfi); ++ support_next_to_fault_free (&ntfo); ++ ++ return 0; ++} ++ ++#include diff --git a/glibc-RHEL-172710-4.patch b/glibc-RHEL-172710-4.patch new file mode 100644 index 0000000..12a03cd --- /dev/null +++ b/glibc-RHEL-172710-4.patch @@ -0,0 +1,193 @@ +commit 6cebb0b80fd783e442a8ad27c3f52cde52a9cac7 +Author: DJ Delorie +Date: Wed May 27 12:57:10 2026 -0400 + + stdio-common: Allow partially-filled %mc buffers [BZ #12701] + + This is a backwards-compatible alternative to the main solution to + the %mc part of 12701. The allocated buffer is expanded to the + requested size and NUL padded, but truncated reads are allowed. + + Reviewed-by: Carlos O'Donell + +Conflicts: + localedata/Makefile + stdio-common/Makefile + (usual test differences) + +diff -Nrup a/localedata/Makefile b/localedata/Makefile +--- a/localedata/Makefile 2026-06-16 10:00:37.802495527 -0400 ++++ b/localedata/Makefile 2026-06-16 09:59:09.766677507 -0400 +@@ -161,6 +161,7 @@ tests = \ + bug-setlocale1 \ + bug-usesetlocale \ + tst-bz12701-lc \ ++ tst-bz12701-lc2 \ + tst-c-utf8-consistency \ + tst-digits \ + tst-iconv-math-trans \ +diff --git a/localedata/tst-bz12701-lc2.c b/localedata/tst-bz12701-lc2.c +new file mode 100644 +index 0000000000..b24e86df0b +--- /dev/null ++++ b/localedata/tst-bz12701-lc2.c +@@ -0,0 +1,47 @@ ++/* Verify scanf memory handling with the 'c' conversion (BZ #12701). ++ Copyright (C) 2026 Free Software Foundation, Inc. ++ This file is part of the GNU C Library. ++ ++ The GNU C Library is free software; you can redistribute it and/or ++ modify it under the terms of the GNU Lesser General Public ++ License as published by the Free Software Foundation; either ++ version 2.1 of the License, or (at your option) any later version. ++ ++ The GNU C Library is distributed in the hope that it will be useful, ++ but WITHOUT ANY WARRANTY; without even the implied warranty of ++ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU ++ Lesser General Public License for more details. ++ ++ You should have received a copy of the GNU Lesser General Public ++ License along with the GNU C Library; if not, see ++ . */ ++ ++#include ++#include ++#include ++ ++#include ++#include ++#include ++#include ++ ++static int ++do_test (void) ++{ ++ wchar_t *c = NULL; ++ int i; ++ ++ TEST_VERIFY (sscanf ("1234", "%30mlc", &c) == 1); ++ ++ TEST_VERIFY (c != NULL); ++ TEST_COMPARE_BLOB (c, 5 * sizeof (wchar_t), ++ L"1234\0", 5 * sizeof (wchar_t)); ++ for (i = 5; i < 30; i ++) ++ TEST_VERIFY (c[i] == L'\0'); ++ ++ TEST_VERIFY (malloc_usable_size (c) >= 30 * sizeof(wchar_t)); ++ ++ return 0; ++} ++ ++#include +diff -Nrup a/stdio-common/Makefile b/stdio-common/Makefile +--- a/stdio-common/Makefile 2026-06-16 10:00:37.803143281 -0400 ++++ b/stdio-common/Makefile 2026-06-16 09:59:54.974421920 -0400 +@@ -218,6 +218,7 @@ tests := \ + tst-bz11319 \ + tst-bz11319-fortify2 \ + tst-bz12701-c \ ++ tst-bz12701-c2 \ + tst-cookie \ + tst-fclose-devzero \ + tst-fclose-offset \ +diff --git a/stdio-common/tst-bz12701-c2.c b/stdio-common/tst-bz12701-c2.c +new file mode 100644 +index 0000000000..5f9ca7c592 +--- /dev/null ++++ b/stdio-common/tst-bz12701-c2.c +@@ -0,0 +1,46 @@ ++/* Verify scanf memory handling with the 'c' conversion (BZ #12701). ++ Copyright (C) 2026 Free Software Foundation, Inc. ++ This file is part of the GNU C Library. ++ ++ The GNU C Library is free software; you can redistribute it and/or ++ modify it under the terms of the GNU Lesser General Public ++ License as published by the Free Software Foundation; either ++ version 2.1 of the License, or (at your option) any later version. ++ ++ The GNU C Library is distributed in the hope that it will be useful, ++ but WITHOUT ANY WARRANTY; without even the implied warranty of ++ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU ++ Lesser General Public License for more details. ++ ++ You should have received a copy of the GNU Lesser General Public ++ License along with the GNU C Library; if not, see ++ . */ ++ ++#include ++#include ++#include ++ ++#include ++#include ++#include ++#include ++ ++static int ++do_test (void) ++{ ++ char *c = NULL; ++ int i; ++ ++ TEST_VERIFY (sscanf ("1234", "%30mc", &c) == 1); ++ ++ TEST_VERIFY (c != NULL); ++ TEST_COMPARE_BLOB (c, 5, "1234\0", 5); ++ for (i = 5; i < 30; i ++) ++ TEST_VERIFY (c[i] == '\0'); ++ ++ TEST_VERIFY (malloc_usable_size (c) >= 30); ++ ++ return 0; ++} ++ ++#include +diff --git a/stdio-common/vfscanf-internal.c b/stdio-common/vfscanf-internal.c +index 17b5565d0f..90a1886951 100644 +--- a/stdio-common/vfscanf-internal.c ++++ b/stdio-common/vfscanf-internal.c +@@ -780,9 +780,9 @@ __vfscanf_internal (FILE *s, const char *format, va_list argptr, + conv_error (); \ + } while (0) + #ifdef COMPILE_WSCANF +- STRING_ARG (str, char, 100); ++ STRING_ARG (str, char, (width > 0 ? width : 1)); + #else +- STRING_ARG (str, char, (width > 1024 ? 1024 : width)); ++ STRING_ARG (str, char, (width > 0 ? width : 1)); + #endif + + c = inchar (); +@@ -891,6 +891,11 @@ __vfscanf_internal (FILE *s, const char *format, va_list argptr, + + if (!(flags & SUPPRESS)) + { ++ /* If the buffer isn't completely filled, pad it with NULs. */ ++ if (flags & MALLOC) ++ while (width-- > 0) ++ *str++ = '\0'; ++ + if ((flags & MALLOC) && str - *strptr != strsize) + { + char *cp = (char *) realloc (*strptr, str - *strptr); +@@ -908,7 +913,7 @@ __vfscanf_internal (FILE *s, const char *format, va_list argptr, + if (width == -1) + width = 1; + +- STRING_ARG (wstr, wchar_t, (width > 1024 ? 1024 : width)); ++ STRING_ARG (wstr, wchar_t, (width > 0 ? width : 1)); + + c = inchar (); + if (__glibc_unlikely (c == EOF)) +@@ -1044,6 +1049,11 @@ __vfscanf_internal (FILE *s, const char *format, va_list argptr, + + if (!(flags & SUPPRESS)) + { ++ /* If the buffer isn't completely filled, pad it with NULs. */ ++ if (flags & MALLOC) ++ while (width-- > 0) ++ *wstr++ = L'\0'; ++ + if ((flags & MALLOC) && wstr - (wchar_t *) *strptr != strsize) + { + wchar_t *cp = (wchar_t *) realloc (*strptr,