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Validate that enough input remains for a complete pathComponent header before accessing it. Reject malformed symlink data that would otherwise make udf_pc_to_char() perform an out-of-bounds read. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: David Lee Assisted-by: Codex:gpt-5.5 --- Trail of Bits has a reproducer that triggers a kernel panic demonstrating this bug and can share it if needed. fs/udf/symlink.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/udf/symlink.c b/fs/udf/symlink.c index fe03745..a05d188 100644 --- a/fs/udf/symlink.c +++ b/fs/udf/symlink.c @@ -36,6 +36,8 @@ static int udf_pc_to_char(struct super_block *sb, unsigned char *from, /* Reserve one byte for terminating \0 */ tolen--; while (elen < fromlen) { + if (fromlen - elen < sizeof(struct pathComponent)) + return -EIO; pc = (struct pathComponent *)(from + elen); elen += sizeof(struct pathComponent); switch (pc->componentType) {