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Message-Id: <20240705-bnxt-str-v1-1-bafc769ed89e@kernel.org>
Date: Fri, 05 Jul 2024 12:26:47 +0100
From: Simon Horman <horms@...nel.org>
To: "David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>
Cc: Michael Chan <michael.chan@...adcom.com>, netdev@...r.kernel.org
Subject: [PATCH net-next 1/3] bnxt_en: check for fw_ver_str truncation
Given the sizes of the buffers involved, it is theoretically
possible for fw_ver_str to be truncated. Detect this and
stop ethtool initialisation if this occurs.
Flagged by gcc-14:
.../bnxt_ethtool.c: In function 'bnxt_ethtool_init':
drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c:4144:32: warning: '%s' directive output may be truncated writing up to 31 bytes into a region of size 26 [-Wformat-truncation=]
4144 | "/pkg %s", buf);
| ^~ ~~~
In function 'bnxt_get_pkgver',
inlined from 'bnxt_ethtool_init' at .../bnxt_ethtool.c:5056:3:
.../bnxt_ethtool.c:4143:17: note: 'snprintf' output between 6 and 37 bytes into a destination of size 31
4143 | snprintf(bp->fw_ver_str + len, FW_VER_STR_LEN - len - 1,
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
4144 | "/pkg %s", buf);
| ~~~~~~~~~~~~~~~
Compile tested only.
Signed-off-by: Simon Horman <horms@...nel.org>
---
It appears to me that size is underestimated by 1 byte -
it should be FW_VER_STR_LEN - offset rather than FW_VER_STR_LEN - offset - 1,
because the size argument to snprintf should include the space for the
trailing '\0'. But I have not changed that as it is separate from
the issue this patch addresses.
---
drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c | 23 ++++++++++++++++-------
1 file changed, 16 insertions(+), 7 deletions(-)
diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c b/drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c
index bf157f6cc042..5ccc3cc4ba7d 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c
@@ -4132,17 +4132,23 @@ int bnxt_get_pkginfo(struct net_device *dev, char *ver, int size)
return rc;
}
-static void bnxt_get_pkgver(struct net_device *dev)
+static int bnxt_get_pkgver(struct net_device *dev)
{
struct bnxt *bp = netdev_priv(dev);
char buf[FW_VER_STR_LEN];
- int len;
if (!bnxt_get_pkginfo(dev, buf, sizeof(buf))) {
- len = strlen(bp->fw_ver_str);
- snprintf(bp->fw_ver_str + len, FW_VER_STR_LEN - len - 1,
- "/pkg %s", buf);
+ int offset, size, rc;
+
+ offset = strlen(bp->fw_ver_str);
+ size = FW_VER_STR_LEN - offset - 1;
+
+ rc = snprintf(bp->fw_ver_str + offset, size, "/pkg %s", buf);
+ if (rc >= size)
+ return -E2BIG;
}
+
+ return 0;
}
static int bnxt_get_eeprom(struct net_device *dev,
@@ -5052,8 +5058,11 @@ void bnxt_ethtool_init(struct bnxt *bp)
struct net_device *dev = bp->dev;
int i, rc;
- if (!(bp->fw_cap & BNXT_FW_CAP_PKG_VER))
- bnxt_get_pkgver(dev);
+ if (!(bp->fw_cap & BNXT_FW_CAP_PKG_VER)) {
+ rc = bnxt_get_pkgver(dev);
+ if (rc)
+ return;
+ }
bp->num_tests = 0;
if (bp->hwrm_spec_code < 0x10704 || !BNXT_PF(bp))
--
2.43.0
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