From: Daniel Wagner wagi@kernel.org
[ Upstream commit ae82eaf4aeea060bb736c3e20c0568b67c701d7d ]
The strlcat() with FORTIFY support is triggering a panic because it thinks the target buffer will overflow although the correct target buffer size is passed in.
Anyway, instead of memset() with 0 followed by a strlcat(), just use memcpy() and ensure that the resulting buffer is NULL terminated.
BIOSVersion is only used for the lpfc_printf_log() which expects a properly terminated string.
Signed-off-by: Daniel Wagner wagi@kernel.org Link: https://lore.kernel.org/r/20250409-fix-lpfc-bios-str-v1-1-05dac9e51e13@kerne... Reviewed-by: Justin Tee justin.tee@broadcom.com Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org ---
Let me understand the actual problem by examining the function more carefully. Based on the commit message, this is about a FORTIFY panic when using strlcat(): **YES** This commit should be backported to stable kernel trees. Here's my extensive analysis: ## Bug Analysis **Root Cause:** The commit fixes a kernel panic triggered by FORTIFY_SOURCE when using `strlcat()`. The FORTIFY infrastructure incorrectly detected a potential buffer overflow in the BIOS version string handling code. **The Problem Code:** ```c memset(phba->BIOSVersion, 0, sizeof(phba->BIOSVersion)); strlcat(phba->BIOSVersion, (char *)cntl_attr->bios_ver_str, sizeof(phba->BIOSVersion)); ``` **The Fix:** ```c memcpy(phba->BIOSVersion, cntl_attr->bios_ver_str, sizeof(phba->BIOSVersion)); phba->BIOSVersion[sizeof(phba->BIOSVersion) - 1] = '\0'; ``` ## Technical Details 1. **Buffer Sizes:** `BIOSVersion` is a 16-byte character array (`char BIOSVersion[16]` in lpfc.h:1267), while `bios_ver_str` is a 32-byte array (`uint32_t bios_ver_str[8]` in lpfc_hw4.h:3798). 2. **FORTIFY Issue:** The `strlcat()` function with FORTIFY enabled was triggering a false positive, causing kernel panics when it incorrectly calculated potential overflow conditions. 3. **Safe Solution:** The fix uses `memcpy()` for the exact buffer size and explicitly null-terminates the string, which is simpler and avoids the FORTIFY false positive. ## Backport Criteria Analysis ✅ **Fixes Important Bug:** This resolves kernel panics in production systems with FORTIFY enabled ✅ **Small & Contained:** Only 3 lines changed in a single function ✅ **Minimal Risk:** The change is functionally equivalent but safer ✅ **No Architectural Changes:** Simple string handling improvement ✅ **Clear Side Effects:** No behavioral changes beyond fixing the panic ✅ **Critical Subsystem:** SCSI driver stability is important for storage ## Comparison with Similar Commits This closely resembles **Similar Commit #2** (marked YES for backport) which fixed an overflow build issue with FORTIFY. Both commits: - Address FORTIFY- related compilation/runtime issues - Make minimal, safe code changes - Fix real problems affecting users - Have low regression risk ## Risk Assessment **Low Risk:** The change maintains identical functionality while eliminating the false positive. Both code paths copy BIOS version data into a 16-byte buffer and ensure null termination. The `memcpy()` approach is actually more predictable than `strlcat()` with an empty target buffer. ## Conclusion This commit fixes a real kernel panic issue that affects users running kernels with FORTIFY_SOURCE enabled. The fix is minimal, safe, and follows stable tree guidelines perfectly. It should definitely be backported to prevent production systems from experiencing these panics.
drivers/scsi/lpfc/lpfc_sli.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/scsi/lpfc/lpfc_sli.c b/drivers/scsi/lpfc/lpfc_sli.c index 68b015bb6d157..fb139e1e35ca3 100644 --- a/drivers/scsi/lpfc/lpfc_sli.c +++ b/drivers/scsi/lpfc/lpfc_sli.c @@ -5926,9 +5926,9 @@ lpfc_sli4_get_ctl_attr(struct lpfc_hba *phba) phba->sli4_hba.flash_id = bf_get(lpfc_cntl_attr_flash_id, cntl_attr); phba->sli4_hba.asic_rev = bf_get(lpfc_cntl_attr_asic_rev, cntl_attr);
- memset(phba->BIOSVersion, 0, sizeof(phba->BIOSVersion)); - strlcat(phba->BIOSVersion, (char *)cntl_attr->bios_ver_str, + memcpy(phba->BIOSVersion, cntl_attr->bios_ver_str, sizeof(phba->BIOSVersion)); + phba->BIOSVersion[sizeof(phba->BIOSVersion) - 1] = '\0';
lpfc_printf_log(phba, KERN_INFO, LOG_SLI, "3086 lnk_type:%d, lnk_numb:%d, bios_ver:%s, "