From: Ibrahim Hashimov Date: Sun, 12 Jul 2026 18:37:39 +0000 (+0200) Subject: scsi: scsi_debug: Fix REPORT ZONES alloc_len underflow OOB write X-Git-Tag: v7.2-rc6~7^2~6 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=93dde0bf2f39a0f9f57fd610aa3201ce5b753433;p=thirdparty%2Flinux.git scsi: scsi_debug: Fix REPORT ZONES alloc_len underflow OOB write resp_report_zones() sizes the reply buffer from the CDB allocation length. The v3 fix rounds alloc_len up with ALIGN() before deriving the descriptor count: rep_max_zones = (ALIGN((u64)alloc_len, RZONES_DESC_HD) - RZONES_DESC_HD) >> ilog2(RZONES_DESC_HD); arr_len = (u64)RZONES_DESC_HD * (rep_max_zones + 1); For alloc_len in 0xFFFFFFC1..0xFFFFFFFF, ALIGN() rounds up to 0x100000000, so arr_len is 4 GB. On 32-bit, kzalloc()'s size_t is 32-bit and truncates 0x100000000 to 0; kzalloc(0) returns ZERO_SIZE_PTR, which passes the !arr check, and desc = arr + 64 is then dereferenced in the loop -> out-of-bounds write / panic. Clamp rep_max_zones to devip->nr_zones. The loop already stops at sdebug_capacity (after nr_zones zones), so a report can never hold more than nr_zones descriptors; the clamp does not change the report, it only bounds arr_len to (nr_zones + 1) * RZONES_DESC_HD, a real device property that can never reach 0x100000000. Fixes: 7db0e0c8190a ("scsi: scsi_debug: Fix buffer size of REPORT ZONES command") Suggested-by: Damien Le Moal Cc: stable@vger.kernel.org Signed-off-by: Ibrahim Hashimov Assisted-by: AuditCode-AI:2026.07 Reviewed-by: Damien Le Moal Reviewed-by: Bart Van Assche Link: https://patch.msgid.link/20260712183739.83915-1-security@auditcode.ai Signed-off-by: Martin K. Petersen --- diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c index 9d1c9c41d0f9..643051332132 100644 --- a/drivers/scsi/scsi_debug.c +++ b/drivers/scsi/scsi_debug.c @@ -5890,6 +5890,7 @@ static int resp_report_zones(struct scsi_cmnd *scp, u32 alloc_len, rep_opts, rep_len; bool partial; u64 lba, zs_lba; + u64 arr_len; u8 *arr = NULL, *desc; u8 *cmd = scp->cmnd; struct sdeb_zone_state *zsp = NULL; @@ -5911,9 +5912,12 @@ static int resp_report_zones(struct scsi_cmnd *scp, return check_condition_result; } - rep_max_zones = (alloc_len - 64) >> ilog2(RZONES_DESC_HD); + rep_max_zones = (ALIGN((u64)alloc_len, RZONES_DESC_HD) - RZONES_DESC_HD) >> + ilog2(RZONES_DESC_HD); + rep_max_zones = min_t(unsigned int, rep_max_zones, devip->nr_zones); + arr_len = (u64)RZONES_DESC_HD * (rep_max_zones + 1); - arr = kzalloc(alloc_len, GFP_ATOMIC | __GFP_NOWARN); + arr = kzalloc(arr_len, GFP_ATOMIC | __GFP_NOWARN); if (!arr) { mk_sense_buffer(scp, ILLEGAL_REQUEST, INSUFF_RES_ASC, INSUFF_RES_ASCQ);