[OE-core] [PATCH 1/1] squashfs: fix CVE-2012-4025
Saul Wold
sgw at linux.intel.com
Tue Dec 11 19:04:57 UTC 2012
On 12/11/2012 02:00 AM, yanjun.zhu wrote:
> From: "yanjun.zhu" <yanjun.zhu at windriver.com>
>
> CQID:WIND00366813
>
> Reference: http://squashfs.git.sourceforge.net/git/gitweb.cgi?
> p=squashfs/squashfs;a=patch;h=8515b3d420f502c5c0236b86e2d6d7e3b23c190e
>
> Integer overflow in the queue_init function in unsquashfs.c in
> unsquashfs in Squashfs 4.2 and earlier allows remote attackers
> to execute arbitrary code via a crafted block_log field in the
> superblock of a .sqsh file, leading to a heap-based buffer overflow.
>
> http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2012-4025
>
> Signed-off-by: yanjun.zhu <yanjun.zhu at windriver.com>
>
This was merged on Nov 30th, or is shit intended for danny, possibly denzil.
Sau!
> [YOCTO #3564]
> ---
> .../patches/squashfs-4.2-fix-CVE-2012-4025.patch | 190 ++++++++++++++++++
> ...dd-a-commment-and-fix-some-other-comments.patch | 38 ++++
> .../patches/squashfs-fix-open-file-limit.patch | 215 +++++++++++++++++++++
> .../squashfs-tools/squashfs-tools_4.2.bb | 3 +
> 4 files changed, 446 insertions(+)
> create mode 100644 meta/recipes-devtools/squashfs-tools/patches/squashfs-4.2-fix-CVE-2012-4025.patch
> create mode 100644 meta/recipes-devtools/squashfs-tools/patches/squashfs-add-a-commment-and-fix-some-other-comments.patch
> create mode 100644 meta/recipes-devtools/squashfs-tools/patches/squashfs-fix-open-file-limit.patch
>
> diff --git a/meta/recipes-devtools/squashfs-tools/patches/squashfs-4.2-fix-CVE-2012-4025.patch b/meta/recipes-devtools/squashfs-tools/patches/squashfs-4.2-fix-CVE-2012-4025.patch
> new file mode 100644
> index 0000000..0dabfba
> --- /dev/null
> +++ b/meta/recipes-devtools/squashfs-tools/patches/squashfs-4.2-fix-CVE-2012-4025.patch
> @@ -0,0 +1,190 @@
> +Upstream-Status: Backport
> +
> +Reference: http://squashfs.git.sourceforge.net/git/gitweb.cgi?
> +p=squashfs/squashfs;a=patch;h=8515b3d420f502c5c0236b86e2d6d7e3b23c190e
> +
> +Integer overflow in the queue_init function in unsquashfs.c in
> +unsquashfs in Squashfs 4.2 and earlier allows remote attackers
> +to execute arbitrary code via a crafted block_log field in the
> +superblock of a .sqsh file, leading to a heap-based buffer overflow.
> +
> +http://web.nvd.nist.gov/view/vuln/detail?vulnId=CVE-2012-4025
> +
> +Signed-off-by: yanjun.zhu <yanjun.zhu at windriver.com>
> +
> +--- a/unsquashfs.c 2012-11-30 17:57:57.000000000 +0800
> ++++ b/unsquashfs.c 2012-11-30 17:58:09.000000000 +0800
> +@@ -33,6 +33,7 @@
> + #include <sys/types.h>
> + #include <sys/time.h>
> + #include <sys/resource.h>
> ++#include <limits.h>
> +
> + struct cache *fragment_cache, *data_cache;
> + struct queue *to_reader, *to_deflate, *to_writer, *from_writer;
> +@@ -138,6 +139,24 @@ void sigalrm_handler()
> + }
> +
> +
> ++int add_overflow(int a, int b)
> ++{
> ++ return (INT_MAX - a) < b;
> ++}
> ++
> ++
> ++int shift_overflow(int a, int shift)
> ++{
> ++ return (INT_MAX >> shift) < a;
> ++}
> ++
> ++
> ++int multiply_overflow(int a, int multiplier)
> ++{
> ++ return (INT_MAX / multiplier) < a;
> ++}
> ++
> ++
> + struct queue *queue_init(int size)
> + {
> + struct queue *queue = malloc(sizeof(struct queue));
> +@@ -145,6 +164,10 @@ struct queue *queue_init(int size)
> + if(queue == NULL)
> + EXIT_UNSQUASH("Out of memory in queue_init\n");
> +
> ++ if(add_overflow(size, 1) ||
> ++ multiply_overflow(size + 1, sizeof(void *)))
> ++ EXIT_UNSQUASH("Size too large in queue_init\n");
> ++
> + queue->data = malloc(sizeof(void *) * (size + 1));
> + if(queue->data == NULL)
> + EXIT_UNSQUASH("Out of memory in queue_init\n");
> +@@ -1948,13 +1971,30 @@ void initialise_threads(int fragment_buf
> + * allocate to_reader, to_deflate and to_writer queues. Set based on
> + * open file limit and cache size, unless open file limit is unlimited,
> + * in which case set purely based on cache limits
> ++ *
> ++ * In doing so, check that the user supplied values do not overflow
> ++ * a signed int
> + */
> + if (max_files != -1) {
> ++ if(add_overflow(data_buffer_size, max_files) ||
> ++ add_overflow(data_buffer_size, max_files * 2))
> ++ EXIT_UNSQUASH("Data queue size is too large\n");
> ++
> + to_reader = queue_init(max_files + data_buffer_size);
> + to_deflate = queue_init(max_files + data_buffer_size);
> + to_writer = queue_init(max_files * 2 + data_buffer_size);
> + } else {
> +- int all_buffers_size = fragment_buffer_size + data_buffer_size;
> ++ int all_buffers_size;
> ++
> ++ if(add_overflow(fragment_buffer_size, data_buffer_size))
> ++ EXIT_UNSQUASH("Data and fragment queues combined are"
> ++ " too large\n");
> ++
> ++ all_buffers_size = fragment_buffer_size + data_buffer_size;
> ++
> ++ if(add_overflow(all_buffers_size, all_buffers_size))
> ++ EXIT_UNSQUASH("Data and fragment queues combined are"
> ++ " too large\n");
> +
> + to_reader = queue_init(all_buffers_size);
> + to_deflate = queue_init(all_buffers_size);
> +@@ -2059,6 +2099,32 @@ void progress_bar(long long current, lon
> + }
> +
> +
> ++int parse_number(char *arg, int *res)
> ++{
> ++ char *b;
> ++ long number = strtol(arg, &b, 10);
> ++
> ++ /* check for trailing junk after number */
> ++ if(*b != '\0')
> ++ return 0;
> ++
> ++ /* check for strtol underflow or overflow in conversion */
> ++ if(number == LONG_MIN || number == LONG_MAX)
> ++ return 0;
> ++
> ++ /* reject negative numbers as invalid */
> ++ if(number < 0)
> ++ return 0;
> ++
> ++ /* check if long result will overflow signed int */
> ++ if(number > INT_MAX)
> ++ return 0;
> ++
> ++ *res = number;
> ++ return 1;
> ++}
> ++
> ++
> + #define VERSION() \
> + printf("unsquashfs version 4.2 (2011/02/28)\n");\
> + printf("copyright (C) 2011 Phillip Lougher "\
> +@@ -2140,8 +2206,8 @@ int main(int argc, char *argv[])
> + } else if(strcmp(argv[i], "-data-queue") == 0 ||
> + strcmp(argv[i], "-da") == 0) {
> + if((++i == argc) ||
> +- (data_buffer_size = strtol(argv[i], &b,
> +- 10), *b != '\0')) {
> ++ !parse_number(argv[i],
> ++ &data_buffer_size)) {
> + ERROR("%s: -data-queue missing or invalid "
> + "queue size\n", argv[0]);
> + exit(1);
> +@@ -2154,8 +2220,8 @@ int main(int argc, char *argv[])
> + } else if(strcmp(argv[i], "-frag-queue") == 0 ||
> + strcmp(argv[i], "-fr") == 0) {
> + if((++i == argc) ||
> +- (fragment_buffer_size = strtol(argv[i],
> +- &b, 10), *b != '\0')) {
> ++ !parse_number(argv[i],
> ++ &fragment_buffer_size)) {
> + ERROR("%s: -frag-queue missing or invalid "
> + "queue size\n", argv[0]);
> + exit(1);
> +@@ -2280,11 +2346,39 @@ options:
> + block_log = sBlk.s.block_log;
> +
> + /*
> ++ * Sanity check block size and block log.
> ++ *
> ++ * Check they're within correct limits
> ++ */
> ++ if(block_size > SQUASHFS_FILE_MAX_SIZE ||
> ++ block_log > SQUASHFS_FILE_MAX_LOG)
> ++ EXIT_UNSQUASH("Block size or block_log too large."
> ++ " File system is corrupt.\n");
> ++
> ++ /*
> ++ * Check block_size and block_log match
> ++ */
> ++ if(block_size != (1 << block_log))
> ++ EXIT_UNSQUASH("Block size and block_log do not match."
> ++ " File system is corrupt.\n");
> ++
> ++ /*
> + * convert from queue size in Mbytes to queue size in
> +- * blocks
> ++ * blocks.
> ++ *
> ++ * In doing so, check that the user supplied values do not
> ++ * overflow a signed int
> + */
> +- fragment_buffer_size <<= 20 - block_log;
> +- data_buffer_size <<= 20 - block_log;
> ++ if(shift_overflow(fragment_buffer_size, 20 - block_log))
> ++ EXIT_UNSQUASH("Fragment queue size is too large\n");
> ++ else
> ++ fragment_buffer_size <<= 20 - block_log;
> ++
> ++ if(shift_overflow(data_buffer_size, 20 - block_log))
> ++ EXIT_UNSQUASH("Data queue size is too large\n");
> ++ else
> ++ data_buffer_size <<= 20 - block_log;
> ++
> + initialise_threads(fragment_buffer_size, data_buffer_size);
> +
> + fragment_data = malloc(block_size);
> diff --git a/meta/recipes-devtools/squashfs-tools/patches/squashfs-add-a-commment-and-fix-some-other-comments.patch b/meta/recipes-devtools/squashfs-tools/patches/squashfs-add-a-commment-and-fix-some-other-comments.patch
> new file mode 100644
> index 0000000..fa075f9
> --- /dev/null
> +++ b/meta/recipes-devtools/squashfs-tools/patches/squashfs-add-a-commment-and-fix-some-other-comments.patch
> @@ -0,0 +1,38 @@
> +Upstream-Status: Backport
> +
> +unsquashfs: add a commment and fix some other comments
> +
> +Signed-off-by: yanjun.zhu <yanjun.zhu at windriver.com>
> +
> +diff -urpN a/unsquashfs.c b/unsquashfs.c
> +--- a/unsquashfs.c 2012-11-30 15:27:14.000000000 +0800
> ++++ b/unsquashfs.c 2012-11-30 15:27:56.000000000 +0800
> +@@ -814,7 +814,7 @@ int write_file(struct inode *inode, char
> +
> + /*
> + * the writer thread is queued a squashfs_file structure describing the
> +- * file. If the file has one or more blocks or a fragments they are
> ++ * file. If the file has one or more blocks or a fragment they are
> + * queued separately (references to blocks in the cache).
> + */
> + file->fd = file_fd;
> +@@ -838,7 +838,7 @@ int write_file(struct inode *inode, char
> + block->offset = 0;
> + block->size = i == file_end ? inode->data & (block_size - 1) :
> + block_size;
> +- if(block_list[i] == 0) /* sparse file */
> ++ if(block_list[i] == 0) /* sparse block */
> + block->buffer = NULL;
> + else {
> + block->buffer = cache_get(data_cache, start,
> +@@ -2161,6 +2161,10 @@ options:
> + block_size = sBlk.s.block_size;
> + block_log = sBlk.s.block_log;
> +
> ++ /*
> ++ * convert from queue size in Mbytes to queue size in
> ++ * blocks
> ++ */
> + fragment_buffer_size <<= 20 - block_log;
> + data_buffer_size <<= 20 - block_log;
> + initialise_threads(fragment_buffer_size, data_buffer_size);
> diff --git a/meta/recipes-devtools/squashfs-tools/patches/squashfs-fix-open-file-limit.patch b/meta/recipes-devtools/squashfs-tools/patches/squashfs-fix-open-file-limit.patch
> new file mode 100644
> index 0000000..c60f7b4
> --- /dev/null
> +++ b/meta/recipes-devtools/squashfs-tools/patches/squashfs-fix-open-file-limit.patch
> @@ -0,0 +1,215 @@
> +Upstream-Status: Backport
> +
> +unsquashfs: fix open file limit
> +
> +Previously Unsquashfs relied on the to_writer queue being
> +set to 1000 to limit the amount of open file read-ahead to a
> +maximum of 500. For the default process limit of 1024 open files
> +this was perhaps acceptable, but it obviously breaks if ulimit has
> +been used to set the open file limit to below 504 (this includes
> +stdin, stdout, stderr and the Squashfs filesystem being unsquashed).
> +
> +More importantly setting the to_writer queue to 1000 to limit
> +the amount of files open has always been an inherent performance
> +hit because the to_writer queue queues blocks. It limits the
> +block readhead to 1000 blocks, irrespective of how many files
> +that represents. A single file containing more than 1000 blocks
> +will still be limited to a 1000 block readahead even though the
> +data block cache typically can buffer more than this (at the
> +default data cache size of 256 Mbytes and the default block size
> +of 128 Kbytes, it can buffer 2048 blocks). Obviously the
> +caches serve more than just a read-ahead role (they also
> +cache decompressed blocks in case they're referenced later e.g.
> +by duplicate files), but the artificial limit imposed on
> +the read-ahead due to setting the to_writer queue to 1000 is
> +unnecessary.
> +
> +This commit does away with the need to limit the to_writer queue,
> +by introducing open_wait() and close_wake() calls which correctly
> +track the amount of open files.
> +
> +Signed-off-by: Phillip Lougher <phillip at squashfs.org.uk>
> +
> +Signed-off-by: yanjun.zhu <yanjun.zhu at windriver.com>
> +
> +diff -urpN a/unsquashfs.c b/unsquashfs.c
> +--- a/unsquashfs.c 2012-11-30 15:31:29.000000000 +0800
> ++++ b/unsquashfs.c 2012-11-30 15:32:03.000000000 +0800
> +@@ -31,6 +31,8 @@
> +
> + #include <sys/sysinfo.h>
> + #include <sys/types.h>
> ++#include <sys/time.h>
> ++#include <sys/resource.h>
> +
> + struct cache *fragment_cache, *data_cache;
> + struct queue *to_reader, *to_deflate, *to_writer, *from_writer;
> +@@ -784,6 +786,46 @@ failure:
> + }
> +
> +
> ++pthread_mutex_t open_mutex = PTHREAD_MUTEX_INITIALIZER;
> ++pthread_cond_t open_empty = PTHREAD_COND_INITIALIZER;
> ++int open_unlimited, open_count;
> ++#define OPEN_FILE_MARGIN 10
> ++
> ++
> ++void open_init(int count)
> ++{
> ++ open_count = count;
> ++ open_unlimited = count == -1;
> ++}
> ++
> ++
> ++int open_wait(char *pathname, int flags, mode_t mode)
> ++{
> ++ if (!open_unlimited) {
> ++ pthread_mutex_lock(&open_mutex);
> ++ while (open_count == 0)
> ++ pthread_cond_wait(&open_empty, &open_mutex);
> ++ open_count --;
> ++ pthread_mutex_unlock(&open_mutex);
> ++ }
> ++
> ++ return open(pathname, flags, mode);
> ++}
> ++
> ++
> ++void close_wake(int fd)
> ++{
> ++ close(fd);
> ++
> ++ if (!open_unlimited) {
> ++ pthread_mutex_lock(&open_mutex);
> ++ open_count ++;
> ++ pthread_cond_signal(&open_empty);
> ++ pthread_mutex_unlock(&open_mutex);
> ++ }
> ++}
> ++
> ++
> + int write_file(struct inode *inode, char *pathname)
> + {
> + unsigned int file_fd, i;
> +@@ -794,8 +836,8 @@ int write_file(struct inode *inode, char
> +
> + TRACE("write_file: regular file, blocks %d\n", inode->blocks);
> +
> +- file_fd = open(pathname, O_CREAT | O_WRONLY | (force ? O_TRUNC : 0),
> +- (mode_t) inode->mode & 0777);
> ++ file_fd = open_wait(pathname, O_CREAT | O_WRONLY |
> ++ (force ? O_TRUNC : 0), (mode_t) inode->mode & 0777);
> + if(file_fd == -1) {
> + ERROR("write_file: failed to create file %s, because %s\n",
> + pathname, strerror(errno));
> +@@ -1712,7 +1754,7 @@ void *writer(void *arg)
> + }
> + }
> +
> +- close(file_fd);
> ++ close_wake(file_fd);
> + if(failed == FALSE)
> + set_attributes(file->pathname, file->mode, file->uid,
> + file->gid, file->time, file->xattr, force);
> +@@ -1803,9 +1845,9 @@ void *progress_thread(void *arg)
> +
> + void initialise_threads(int fragment_buffer_size, int data_buffer_size)
> + {
> +- int i;
> ++ struct rlimit rlim;
> ++ int i, max_files, res;
> + sigset_t sigmask, old_mask;
> +- int all_buffers_size = fragment_buffer_size + data_buffer_size;
> +
> + sigemptyset(&sigmask);
> + sigaddset(&sigmask, SIGINT);
> +@@ -1841,10 +1883,86 @@ void initialise_threads(int fragment_buf
> + EXIT_UNSQUASH("Out of memory allocating thread descriptors\n");
> + deflator_thread = &thread[3];
> +
> +- to_reader = queue_init(all_buffers_size);
> +- to_deflate = queue_init(all_buffers_size);
> +- to_writer = queue_init(1000);
> ++ /*
> ++ * dimensioning the to_reader and to_deflate queues. The size of
> ++ * these queues is directly related to the amount of block
> ++ * read-ahead possible. To_reader queues block read requests to
> ++ * the reader thread and to_deflate queues block decompression
> ++ * requests to the deflate thread(s) (once the block has been read by
> ++ * the reader thread). The amount of read-ahead is determined by
> ++ * the combined size of the data_block and fragment caches which
> ++ * determine the total number of blocks which can be "in flight"
> ++ * at any one time (either being read or being decompressed)
> ++ *
> ++ * The maximum file open limit, however, affects the read-ahead
> ++ * possible, in that for normal sizes of the fragment and data block
> ++ * caches, where the incoming files have few data blocks or one fragment
> ++ * only, the file open limit is likely to be reached before the
> ++ * caches are full. This means the worst case sizing of the combined
> ++ * sizes of the caches is unlikely to ever be necessary. However, is is
> ++ * obvious read-ahead up to the data block cache size is always possible
> ++ * irrespective of the file open limit, because a single file could
> ++ * contain that number of blocks.
> ++ *
> ++ * Choosing the size as "file open limit + data block cache size" seems
> ++ * to be a reasonable estimate. We can reasonably assume the maximum
> ++ * likely read-ahead possible is data block cache size + one fragment
> ++ * per open file.
> ++ *
> ++ * dimensioning the to_writer queue. The size of this queue is
> ++ * directly related to the amount of block read-ahead possible.
> ++ * However, unlike the to_reader and to_deflate queues, this is
> ++ * complicated by the fact the to_writer queue not only contains
> ++ * entries for fragments and data_blocks but it also contains
> ++ * file entries, one per open file in the read-ahead.
> ++ *
> ++ * Choosing the size as "2 * (file open limit) +
> ++ * data block cache size" seems to be a reasonable estimate.
> ++ * We can reasonably assume the maximum likely read-ahead possible
> ++ * is data block cache size + one fragment per open file, and then
> ++ * we will have a file_entry for each open file.
> ++ */
> ++ res = getrlimit(RLIMIT_NOFILE, &rlim);
> ++ if (res == -1) {
> ++ ERROR("failed to get open file limit! Defaulting to 1\n");
> ++ rlim.rlim_cur = 1;
> ++ }
> ++
> ++ if (rlim.rlim_cur != RLIM_INFINITY) {
> ++ /*
> ++ * leave OPEN_FILE_MARGIN free (rlim_cur includes fds used by
> ++ * stdin, stdout, stderr and filesystem fd
> ++ */
> ++ if (rlim.rlim_cur <= OPEN_FILE_MARGIN)
> ++ /* no margin, use minimum possible */
> ++ max_files = 1;
> ++ else
> ++ max_files = rlim.rlim_cur - OPEN_FILE_MARGIN;
> ++ } else
> ++ max_files = -1;
> ++
> ++ /* set amount of available files for use by open_wait and close_wake */
> ++ open_init(max_files);
> ++
> ++ /*
> ++ * allocate to_reader, to_deflate and to_writer queues. Set based on
> ++ * open file limit and cache size, unless open file limit is unlimited,
> ++ * in which case set purely based on cache limits
> ++ */
> ++ if (max_files != -1) {
> ++ to_reader = queue_init(max_files + data_buffer_size);
> ++ to_deflate = queue_init(max_files + data_buffer_size);
> ++ to_writer = queue_init(max_files * 2 + data_buffer_size);
> ++ } else {
> ++ int all_buffers_size = fragment_buffer_size + data_buffer_size;
> ++
> ++ to_reader = queue_init(all_buffers_size);
> ++ to_deflate = queue_init(all_buffers_size);
> ++ to_writer = queue_init(all_buffers_size * 2);
> ++ }
> ++
> + from_writer = queue_init(1);
> ++
> + fragment_cache = cache_init(block_size, fragment_buffer_size);
> + data_cache = cache_init(block_size, data_buffer_size);
> + pthread_create(&thread[0], NULL, reader, NULL);
> diff --git a/meta/recipes-devtools/squashfs-tools/squashfs-tools_4.2.bb b/meta/recipes-devtools/squashfs-tools/squashfs-tools_4.2.bb
> index 213a700..5b3e644 100644
> --- a/meta/recipes-devtools/squashfs-tools/squashfs-tools_4.2.bb
> +++ b/meta/recipes-devtools/squashfs-tools/squashfs-tools_4.2.bb
> @@ -14,6 +14,9 @@ SRC_URI = "${SOURCEFORGE_MIRROR}/squashfs/squashfs${PV}.tar.gz;name=squashfs \
> http://downloads.sourceforge.net/sevenzip/lzma465.tar.bz2;name=lzma \
> "
> SRC_URI += "file://squashfs-4.2-fix-CVE-2012-4024.patch \
> + file://squashfs-add-a-commment-and-fix-some-other-comments.patch \
> + file://squashfs-fix-open-file-limit.patch \
> + file://squashfs-4.2-fix-CVE-2012-4025.patch \
> "
>
> SRC_URI[squashfs.md5sum] = "1b7a781fb4cf8938842279bd3e8ee852"
>
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