net/mlx5: fw_tracer, Handle escaped percent properly

The firmware tracer's format string validation and parameter counting
did not properly handle escaped percent signs (%%). This caused
fw_tracer to count more parameters when trace format strings contained
literal percent characters.

To fix it, allow %% to pass string validation and skip %% sequences when
counting parameters since they represent literal percent signs rather
than format specifiers.

Fixes: 70dd6fdb8987 ("net/mlx5: FW tracer, parse traces and kernel tracing support")
Signed-off-by: Shay Drory <shayd@nvidia.com>
Reported-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Moshe Shemesh <moshe@nvidia.com>
Closes: https://lore.kernel.org/netdev/hanz6rzrb2bqbplryjrakvkbmv4y5jlmtthnvi3thg5slqvelp@t3s3erottr6s/
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://patch.msgid.link/1765284977-1363052-5-git-send-email-tariqt@nvidia.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/diag/fw_tracer.c b/drivers/net/ethernet/mellanox/mlx5/core/diag/fw_tracer.c
index b415dfe5de45fc93df8d584931c768d66c93fef8..6b4ec457ce2274960efc52b656c1ba3670040bfe 100644 (file)
--- a/drivers/net/ethernet/mellanox/mlx5/core/diag/fw_tracer.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/diag/fw_tracer.c
@@ -368,11 +368,11 @@ static bool mlx5_is_valid_spec(const char *str)
        while (isdigit(*str) || *str == '#' || *str == '.' || *str == 'l')
                str++;
 
-       /* Check if it's a valid integer/hex specifier:
+       /* Check if it's a valid integer/hex specifier or %%:
         * Valid formats: %x, %d, %i, %u, etc.
         */
        if (*str != 'x' && *str != 'X' && *str != 'd' && *str != 'i' &&
-           *str != 'u' && *str != 'c')
+           *str != 'u' && *str != 'c' && *str != '%')
                return false;
 
        return true;
@@ -390,7 +390,11 @@ static bool mlx5_tracer_validate_params(const char *str)
                if (!mlx5_is_valid_spec(substr + 1))
                        return false;
 
-               substr = strstr(substr + 1, PARAM_CHAR);
+               if (*(substr + 1) == '%')
+                       substr = strstr(substr + 2, PARAM_CHAR);
+               else
+                       substr = strstr(substr + 1, PARAM_CHAR);
+
        }
 
        return true;
@@ -469,11 +473,15 @@ static int mlx5_tracer_get_num_of_params(char *str)
                substr = strstr(pstr, VAL_PARM);
        }
 
-       /* count all the % characters */
+       /* count all the % characters, but skip %% (escaped percent) */
        substr = strstr(str, PARAM_CHAR);
        while (substr) {
-               num_of_params += 1;
-               str = substr + 1;
+               if (*(substr + 1) != '%') {
+                       num_of_params += 1;
+                       str = substr + 1;
+               } else {
+                       str = substr + 2;
+               }
                substr = strstr(str, PARAM_CHAR);
        }