From: David Lee <david.lee@trailofbits.com> stable inclusion from stable-6.6.157 commit b77b83f5529a26d084d64ece98abd6f0cc86e053 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/18864 CVE: CVE-2026-89525 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... ------------------------------ commit cac0cb07f29ccfb373fd4a36c81e908ef3ce608c upstream. UDF 1.50 virtual partition mapping uses the VAT as an array of physical block mappings. s_num_entries stores the number of entries in that array, not the highest valid index. The valid VAT indexes are therefore below s_num_entries. udf_get_pblock_virt15() currently rejects only indexes greater than s_num_entries. A crafted image can request index s_num_entries, pass the bounds check, and make the kernel read one entry past the allocated VAT table. Change the check to reject block >= s_num_entries, so the count is handled as an exclusive upper bound. A crafted UDF image reproduced this on origin/master commit 0e35b9b6ec0ffcc5e23cbdec09f5c622ad532b53 with a KASAN slab-out-of-bounds report in udf_get_pblock_virt15(). Trail of Bits has a reproducer that triggers kernel panic demonstrating the bug, and can share it if needed. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Cc: stable@vger.kernel.org Signed-off-by: David Lee <david.lee@trailofbits.com> Assisted-by: Codex:gpt-5.5 Link: https://patch.msgid.link/20260708101712.1706564-1-david.lee@trailofbits.com Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Lu Jialin <lujialin4@huawei.com> --- fs/udf/partition.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/udf/partition.c b/fs/udf/partition.c index 2b85c9501bed..ad8dcedca263 100644 --- a/fs/udf/partition.c +++ b/fs/udf/partition.c @@ -55,7 +55,7 @@ uint32_t udf_get_pblock_virt15(struct super_block *sb, uint32_t block, map = &sbi->s_partmaps[partition]; vdata = &map->s_type_specific.s_virtual; - if (block > vdata->s_num_entries) { + if (block >= vdata->s_num_entries) { udf_debug("Trying to access block beyond end of VAT (%u max %u)\n", block, vdata->s_num_entries); return 0xFFFFFFFF; -- 2.34.1