From: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
To: keescook@chromium.org, Robert Richter <rric@kernel.org>,
Borislav Petkov <bp@alien8.de>, Tony Luck <tony.luck@intel.com>,
James Morse <james.morse@arm.com>,
Mauro Carvalho Chehab <mchehab@kernel.org>,
Sergey Temerkhanov <s.temerkhanov@gmail.com>
Cc: linux-hardening@vger.kernel.org, linux-kernel@vger.kernel.org,
kernel-janitors@vger.kernel.org,
Christophe JAILLET <christophe.jaillet@wanadoo.fr>,
Borislav Petkov <bp@suse.de>,
linux-edac@vger.kernel.org
Subject: [PATCH] EDAC/thunderx: Fix some potential buffer overflow in thunderx_ocx_com_threaded_isr()
Date: Sat, 21 Oct 2023 19:06:34 +0200 [thread overview]
Message-ID: <a787355ac896903935dd85ac96cddf1a0afa87af.1697903882.git.christophe.jaillet@wanadoo.fr> (raw)
strncat() usage in thunderx_ocx_com_threaded_isr() is wrong.
The size given to strncat() is the maximum number of bytes that can be
written, excluding the trailing NULL.
Here, the size of the 'msg' buffer is used (i.e. OCX_MESSAGE_SIZE), not
the space that is remaining.
The space for the ending NULL is also not taken into account.
in order to fix it:
- call decode_register() before the snprintf() calls
- use scnprintf() instead of snprintf() and compute, in the 'remaining'
variable, the space that is still available in the 'msg' buffer
- add a %s at the end of the format strings and append directly the
result of decode_register() stored in 'other'
- write directly at the right position in the 'msg' buffer when
appending some data in the for loop.
Doing so, all usages of strncat() are removed.
Fixes: 41003396f932 ("EDAC, thunderx: Add Cavium ThunderX EDAC driver")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
---
This is cross-compile tested only.
Review with care.
---
drivers/edac/thunderx_edac.c | 24 ++++++++++++------------
1 file changed, 12 insertions(+), 12 deletions(-)
diff --git a/drivers/edac/thunderx_edac.c b/drivers/edac/thunderx_edac.c
index b9c5772da959..9544836dbd19 100644
--- a/drivers/edac/thunderx_edac.c
+++ b/drivers/edac/thunderx_edac.c
@@ -1111,6 +1111,7 @@ static irqreturn_t thunderx_ocx_com_threaded_isr(int irq, void *irq_id)
unsigned long tail;
struct ocx_com_err_ctx *ctx;
+ size_t remaining;
int lane;
char *msg;
char *other;
@@ -1127,27 +1128,26 @@ static irqreturn_t thunderx_ocx_com_threaded_isr(int irq, void *irq_id)
ARRAY_SIZE(ocx->com_err_ctx));
ctx = &ocx->com_err_ctx[tail];
- snprintf(msg, OCX_MESSAGE_SIZE, "%s: OCX_COM_INT: %016llx",
- ocx->edac_dev->ctl_name, ctx->reg_com_int);
-
decode_register(other, OCX_OTHER_SIZE,
ocx_com_errors, ctx->reg_com_int);
- strncat(msg, other, OCX_MESSAGE_SIZE);
+ remaining = OCX_MESSAGE_SIZE;
+ remaining -= scnprintf(msg, remaining, "%s: OCX_COM_INT: %016llx%s",
+ ocx->edac_dev->ctl_name, ctx->reg_com_int,
+ other);
for (lane = 0; lane < OCX_RX_LANES; lane++)
if (ctx->reg_com_int & BIT(lane)) {
- snprintf(other, OCX_OTHER_SIZE,
- "\n\tOCX_LNE_INT[%02d]: %016llx OCX_LNE_STAT11[%02d]: %016llx",
- lane, ctx->reg_lane_int[lane],
- lane, ctx->reg_lane_stat11[lane]);
-
- strncat(msg, other, OCX_MESSAGE_SIZE);
-
decode_register(other, OCX_OTHER_SIZE,
ocx_lane_errors,
ctx->reg_lane_int[lane]);
- strncat(msg, other, OCX_MESSAGE_SIZE);
+
+ remaining -= scnprintf(msg + (OCX_MESSAGE_SIZE - remaining),
+ remaining,
+ "\n\tOCX_LNE_INT[%02d]: %016llx OCX_LNE_STAT11[%02d]: %016llx%s",
+ lane, ctx->reg_lane_int[lane],
+ lane, ctx->reg_lane_stat11[lane],
+ other);
}
if (ctx->reg_com_int & OCX_COM_INT_CE)
--
2.34.1
reply other threads:[~2023-10-21 17:14 UTC|newest]
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