From: Kees Cook Date: Wed, 16 Apr 2025 02:01:14 +0000 (-0700) Subject: net/mlx5e: ethtool: Fix formatting of ptp_rq0_csum_complete_tail_slow X-Git-Tag: v6.16-rc1~132^2~269 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=cfba1d1b61ae3f32e4bc06e9860711a4488d98b7;p=thirdparty%2Flinux.git net/mlx5e: ethtool: Fix formatting of ptp_rq0_csum_complete_tail_slow The new GCC 15 warning -Wunterminated-string-initialization reports: In file included from drivers/net/ethernet/mellanox/mlx5/core/en.h:55, from drivers/net/ethernet/mellanox/mlx5/core/en_stats.c:34: drivers/net/ethernet/mellanox/mlx5/core/en_stats.h:57:46: warning: initializer-string for array of 'char' truncates NUL terminator but destination lacks 'nonstring' attribute (33 chars into 32 available) [-Wunterminated-string-initialization] 57 | #define MLX5E_DECLARE_PTP_RQ_STAT(type, fld) "ptp_rq%d_"#fld, offsetof(type, fld) | ^~~~~~~~~~~ drivers/net/ethernet/mellanox/mlx5/core/en_stats.c:2279:11: note: in expansion of macro 'MLX5E_DECLARE_PTP_RQ_STAT' 2279 | { MLX5E_DECLARE_PTP_RQ_STAT(struct mlx5e_rq_stats, csum_complete_tail_slow) }, | ^~~~~~~~~~~~~~~~~~~~~~~~~ This stat string is being used in ethtool_sprintf(), so it must be a valid NUL-terminated string. Currently the string lacks the final NUL byte (as GCC warns), but by absolute luck, the next byte in memory is a space (decimal 32) followed by a NUL. "format" is immediately followed by little-endian size_t: struct counter_desc { char format[32]; /* 0 32 */ size_t offset; /* 32 8 */ }; The "offset" member is populated by the stats member offset: #define MLX5E_DECLARE_PTP_RQ_STAT(type, fld) "ptp_rq%d_"#fld, offsetof(type, fld) which for this struct mlx5e_rq_stats member, csum_complete_tail_slow, is 32, or space, and then the rest of the "offset" bytes are NULs. struct mlx5e_rq_stats { ... u64 csum_complete_tail_slow; /* 32 8 */ The use of vsnprintf(), within ethtool_sprintf(), reads past the end of "format" and sees the format string as "ptp_rq%d_csum_complete_tail_slow ", with %d getting resolved by MLX5E_PTP_CHANNEL_IX (value 0): ethtool_sprintf(data, ptp_rq_stats_desc[i].format, MLX5E_PTP_CHANNEL_IX); With an output result of "ptp_rq0_csum_complete_tail_slow", which gets precisely truncated to 31 characters with a trailing NUL. So, instead of accidentally getting this correct due to the NUL bytes at the end of the size_t that happens to follow the format string, just make the string initializer 1 byte shorter by replacing "%d" with "0", since MLX5E_PTP_CHANNEL_IX is already hard-coded. This results in no initializer truncation and no need to call sprintf(). Signed-off-by: Kees Cook Reviewed-by: Dragos Tatulea Link: https://patch.msgid.link/20250416020109.work.297-kees@kernel.org Signed-off-by: Jakub Kicinski --- diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_stats.c b/drivers/net/ethernet/mellanox/mlx5/core/en_stats.c index 1c121b435016d..19664fa7f2171 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_stats.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_stats.c @@ -2424,8 +2424,7 @@ static MLX5E_DECLARE_STATS_GRP_OP_FILL_STRS(ptp) } if (priv->rx_ptp_opened) { for (i = 0; i < NUM_PTP_RQ_STATS; i++) - ethtool_sprintf(data, ptp_rq_stats_desc[i].format, - MLX5E_PTP_CHANNEL_IX); + ethtool_puts(data, ptp_rq_stats_desc[i].format); } } diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_stats.h b/drivers/net/ethernet/mellanox/mlx5/core/en_stats.h index 8de6fcbd3a033..def5dea1463db 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/en_stats.h +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_stats.h @@ -54,7 +54,7 @@ #define MLX5E_DECLARE_PTP_TX_STAT(type, fld) "ptp_tx%d_"#fld, offsetof(type, fld) #define MLX5E_DECLARE_PTP_CH_STAT(type, fld) "ptp_ch_"#fld, offsetof(type, fld) #define MLX5E_DECLARE_PTP_CQ_STAT(type, fld) "ptp_cq%d_"#fld, offsetof(type, fld) -#define MLX5E_DECLARE_PTP_RQ_STAT(type, fld) "ptp_rq%d_"#fld, offsetof(type, fld) +#define MLX5E_DECLARE_PTP_RQ_STAT(type, fld) "ptp_rq0_"#fld, offsetof(type, fld) #define MLX5E_DECLARE_QOS_TX_STAT(type, fld) "qos_tx%d_"#fld, offsetof(type, fld)