The following commit has been merged into the efi/core branch of tip: Commit-ID: 5eff88dd6b4badd664d7d3b648103d540b390248 Gitweb: https://git.kernel.org/tip/5eff88dd6b4badd664d7d3b648103d540b390248 Author: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx> AuthorDate: Wed, 21 Apr 2021 21:31:46 +02:00 Committer: Ard Biesheuvel <ardb@xxxxxxxxxx> CommitterDate: Fri, 27 Aug 2021 16:01:27 +02:00 efi: cper: fix scnprintf() use in cper_mem_err_location() The last two if-clauses fail to update n, so whatever they might have written at &msg[n] would be cut off by the final nul-termination. That nul-termination is redundant; scnprintf(), just like snprintf(), guarantees a nul-terminated output buffer, provided the buffer size is positive. And there's no need to discount one byte from the initial buffer; vsnprintf() expects to be given the full buffer size - it's not going to write the nul-terminator one beyond the given (buffer, size) pair. Signed-off-by: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx> Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx> --- drivers/firmware/efi/cper.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) diff --git a/drivers/firmware/efi/cper.c b/drivers/firmware/efi/cper.c index ea7ca74..1cb7097 100644 --- a/drivers/firmware/efi/cper.c +++ b/drivers/firmware/efi/cper.c @@ -221,7 +221,7 @@ static int cper_mem_err_location(struct cper_mem_err_compact *mem, char *msg) return 0; n = 0; - len = CPER_REC_LEN - 1; + len = CPER_REC_LEN; if (mem->validation_bits & CPER_MEM_VALID_NODE) n += scnprintf(msg + n, len - n, "node: %d ", mem->node); if (mem->validation_bits & CPER_MEM_VALID_CARD) @@ -258,13 +258,12 @@ static int cper_mem_err_location(struct cper_mem_err_compact *mem, char *msg) n += scnprintf(msg + n, len - n, "responder_id: 0x%016llx ", mem->responder_id); if (mem->validation_bits & CPER_MEM_VALID_TARGET_ID) - scnprintf(msg + n, len - n, "target_id: 0x%016llx ", - mem->target_id); + n += scnprintf(msg + n, len - n, "target_id: 0x%016llx ", + mem->target_id); if (mem->validation_bits & CPER_MEM_VALID_CHIP_ID) - scnprintf(msg + n, len - n, "chip_id: %d ", - mem->extended >> CPER_MEM_CHIP_ID_SHIFT); + n += scnprintf(msg + n, len - n, "chip_id: %d ", + mem->extended >> CPER_MEM_CHIP_ID_SHIFT); - msg[n] = '\0'; return n; }
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