diff options
| -rw-r--r-- | ChangeLog | 8 | ||||
| -rw-r--r-- | stdlib/Makefile | 2 | ||||
| -rw-r--r-- | stdlib/canonicalize.c | 2 | ||||
| -rw-r--r-- | stdlib/test-bz22786.c | 90 |
4 files changed, 100 insertions, 2 deletions
diff --git a/ChangeLog b/ChangeLog index 02528b6eb0..4164b32036 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,11 @@ +2018-05-09 Paul Pluzhnikov <ppluzhnikov@google.com> + + [BZ #22786] + * stdlib/canonicalize.c (__realpath): Fix overflow in path length + computation. + * stdlib/Makefile (test-bz22786): New test. + * stdlib/test-bz22786.c: New test. + 2018-05-09 Joseph Myers <joseph@codesourcery.com> * include/math-narrow-eval.h: New file. Contents moved from .... diff --git a/stdlib/Makefile b/stdlib/Makefile index af1643c0c4..1ddb1f9d18 100644 --- a/stdlib/Makefile +++ b/stdlib/Makefile @@ -84,7 +84,7 @@ tests := tst-strtol tst-strtod testmb testrand testsort testdiv \ tst-cxa_atexit tst-on_exit test-atexit-race \ test-at_quick_exit-race test-cxa_atexit-race \ test-on_exit-race test-dlclose-exit-race \ - tst-makecontext-align + tst-makecontext-align test-bz22786 tests-internal := tst-strtod1i tst-strtod3 tst-strtod4 tst-strtod5i \ tst-tls-atexit tst-tls-atexit-nodelete diff --git a/stdlib/canonicalize.c b/stdlib/canonicalize.c index 4135f3f33c..390fb437a8 100644 --- a/stdlib/canonicalize.c +++ b/stdlib/canonicalize.c @@ -181,7 +181,7 @@ __realpath (const char *name, char *resolved) extra_buf = __alloca (path_max); len = strlen (end); - if ((long int) (n + len) >= path_max) + if (path_max - n <= len) { __set_errno (ENAMETOOLONG); goto error; diff --git a/stdlib/test-bz22786.c b/stdlib/test-bz22786.c new file mode 100644 index 0000000000..e7837f98c1 --- /dev/null +++ b/stdlib/test-bz22786.c @@ -0,0 +1,90 @@ +/* Bug 22786: test for buffer overflow in realpath. + Copyright (C) 2018 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 + <http://www.gnu.org/licenses/>. */ + +/* This file must be run from within a directory called "stdlib". */ + +#include <errno.h> +#include <limits.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include <sys/stat.h> +#include <sys/types.h> +#include <support/test-driver.h> +#include <libc-diag.h> + +static int +do_test (void) +{ + const char dir[] = "bz22786"; + const char lnk[] = "bz22786/symlink"; + + rmdir (dir); + if (mkdir (dir, 0755) != 0 && errno != EEXIST) + { + printf ("mkdir %s: %m\n", dir); + return EXIT_FAILURE; + } + if (symlink (".", lnk) != 0 && errno != EEXIST) + { + printf ("symlink (%s, %s): %m\n", dir, lnk); + return EXIT_FAILURE; + } + + const size_t path_len = (size_t) INT_MAX + 1; + + DIAG_PUSH_NEEDS_COMMENT; +#if __GNUC_PREREQ (7, 0) + /* GCC 7 warns about too-large allocations; here we need such + allocation to succeed for the test to work. */ + DIAG_IGNORE_NEEDS_COMMENT (7, "-Walloc-size-larger-than="); +#endif + char *path = malloc (path_len); + DIAG_POP_NEEDS_COMMENT; + + if (path == NULL) + { + printf ("malloc (%zu): %m\n", path_len); + return EXIT_UNSUPPORTED; + } + + /* Construct very long path = "bz22786/symlink/aaaa....." */ + char *p = mempcpy (path, lnk, sizeof (lnk) - 1); + *(p++) = '/'; + memset (p, 'a', path_len - (path - p) - 2); + p[path_len - (path - p) - 1] = '\0'; + + /* This call crashes before the fix for bz22786 on 32-bit platforms. */ + p = realpath (path, NULL); + + if (p != NULL || errno != ENAMETOOLONG) + { + printf ("realpath: %s (%m)", p); + return EXIT_FAILURE; + } + + /* Cleanup. */ + unlink (lnk); + rmdir (dir); + + return 0; +} + +#define TEST_FUNCTION do_test +#include <support/test-driver.c> |