From: Jann Horn <jannh@google.com> mainline inclusion from mainline-v6.10-rc2 commit 80e648042e512d5a767da251d44132553fe04ae0 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IBPC5K CVE: CVE-2025-21772 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- Fix several issues in partition probing: - The bailout for a bad partoffset must use put_dev_sector(), since the preceding read_part_sector() succeeded. - If the partition table claims a silly sector size like 0xfff bytes (which results in partition table entries straddling sector boundaries), bail out instead of accessing out-of-bounds memory. - We must not assume that the partition table contains proper NUL termination - use strnlen() and strncmp() instead of strlen() and strcmp(). Cc: stable@vger.kernel.org Signed-off-by: Jann Horn <jannh@google.com> Link: https://lore.kernel.org/r/20250214-partition-mac-v1-1-c1c626dffbd5@google.co... Signed-off-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Long Li <leo.lilong@huawei.com> --- block/partitions/mac.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) diff --git a/block/partitions/mac.c b/block/partitions/mac.c index b6095335636c..ca619d852757 100644 --- a/block/partitions/mac.c +++ b/block/partitions/mac.c @@ -51,13 +51,25 @@ int mac_partition(struct parsed_partitions *state) } secsize = be16_to_cpu(md->block_size); put_dev_sector(sect); + + /* + * If the "block size" is not a power of 2, things get weird - we might + * end up with a partition straddling a sector boundary, so we wouldn't + * be able to read a partition entry with read_part_sector(). + * Real block sizes are probably (?) powers of two, so just require + * that. + */ + if (!is_power_of_2(secsize)) + return -1; datasize = round_down(secsize, 512); data = read_part_sector(state, datasize / 512, §); if (!data) return -1; partoffset = secsize % 512; - if (partoffset + sizeof(*part) > datasize) + if (partoffset + sizeof(*part) > datasize) { + put_dev_sector(sect); return -1; + } part = (struct mac_partition *) (data + partoffset); if (be16_to_cpu(part->signature) != MAC_PARTITION_MAGIC) { put_dev_sector(sect); @@ -110,8 +122,8 @@ int mac_partition(struct parsed_partitions *state) int i, l; goodness++; - l = strlen(part->name); - if (strcmp(part->name, "/") == 0) + l = strnlen(part->name, sizeof(part->name)); + if (strncmp(part->name, "/", sizeof(part->name)) == 0) goodness++; for (i = 0; i <= l - 4; ++i) { if (strncasecmp(part->name + i, "root", -- 2.39.2