From 44bb09f0ca637ef11525dd37377cda5f49c72e57 Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Thu, 9 Jul 2026 21:36:01 +0200 Subject: [PATCH] dm-verity: increase sprintf buffer size commit 88dd117c92a142253fb7a17e791773902b3babc6 upstream. The prefix "DM_VERITY_ERR_BLOCK_NR" is 22 chars. Add '=', one digit for type, ',', up to 20 digits for a u64 block number, and a NUL terminator: that's 46 bytes. The buffer is 42 bytes. For block numbers >= 16 decimal digits (devices larger than ~16 EB with 4K blocks), snprintf silently truncates the uevent environment variable. Signed-off-by: Mikulas Patocka Assisted-by: Claude:claude-opus-4.6 Fixes: 65ff5b7ddf05 ("dm verity: add error handling modes for corrupted blocks") Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman --- drivers/md/dm-verity-target.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/md/dm-verity-target.c b/drivers/md/dm-verity-target.c index 905764e333e8..b24a475a6600 100644 --- a/drivers/md/dm-verity-target.c +++ b/drivers/md/dm-verity-target.c @@ -21,7 +21,7 @@ #define DM_MSG_PREFIX "verity" -#define DM_VERITY_ENV_LENGTH 42 +#define DM_VERITY_ENV_LENGTH 46 #define DM_VERITY_ENV_VAR_NAME "DM_VERITY_ERR_BLOCK_NR" #define DM_VERITY_DEFAULT_PREFETCH_SIZE 262144