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| author | Florian Weimer <fweimer@redhat.com> | 2012-10-16 10:33:50 +0200 |
|---|---|---|
| committer | Florian Weimer <fweimer@redhat.com> | 2012-10-16 10:33:50 +0200 |
| commit | 172a631a1fc8ec8fcef80af1f91438d092957c3e (patch) | |
| tree | 8cbc1cd11a3e922cb60994ac47018db43e6a8e5f /sysdeps | |
| parent | e9f372520618161d7d73e028ca23818e83b88bbc (diff) | |
| download | glibc-172a631a1fc8ec8fcef80af1f91438d092957c3e.tar glibc-172a631a1fc8ec8fcef80af1f91438d092957c3e.tar.gz glibc-172a631a1fc8ec8fcef80af1f91438d092957c3e.tar.bz2 glibc-172a631a1fc8ec8fcef80af1f91438d092957c3e.zip | |
__alloc_dir: avoid integer overflow in malloc argument
Diffstat (limited to 'sysdeps')
| -rw-r--r-- | sysdeps/posix/opendir.c | 15 |
1 files changed, 11 insertions, 4 deletions
diff --git a/sysdeps/posix/opendir.c b/sysdeps/posix/opendir.c index e093142f62..f1cc1aeb57 100644 --- a/sysdeps/posix/opendir.c +++ b/sysdeps/posix/opendir.c @@ -1,5 +1,4 @@ -/* Copyright (C) 1991-1996,98,2000-2003,2005,2007,2009,2011 - Free Software Foundation, Inc. +/* Copyright (C) 1991-2012 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 @@ -33,6 +32,11 @@ #include <not-cancel.h> #include <kernel-features.h> +/* The st_blksize value of the directory is used as a hint for the + size of the buffer which receives struct dirent values from the + kernel. st_blksize is limited to MAX_DIR_BUFFER_SIZE, in case the + file system provides a bogus value. */ +#define MAX_DIR_BUFFER_SIZE 1048576U /* opendir() must not accidentally open something other than a directory. Some OS's have kernel support for that, some don't. In the worst @@ -192,8 +196,11 @@ __alloc_dir (int fd, bool close_fd, int flags, const struct stat64 *statp) ? sizeof (struct dirent64) : BUFSIZ); size_t allocation = default_allocation; #ifdef _STATBUF_ST_BLKSIZE - if (statp != NULL && default_allocation < statp->st_blksize) - allocation = statp->st_blksize; + /* Increase allocation if requested, but not if the value appears to + be bogus. */ + if (statp != NULL) + allocation = MIN (MAX ((size_t) statp->st_blksize, default_allocation), + MAX_DIR_BUFFER_SIZE); #endif DIR *dirp = (DIR *) malloc (sizeof (DIR) + allocation); |