6.6-stable review patch. If anyone has any objections, please let me know.
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From: Shay Drory shayd@nvidia.com
[ Upstream commit b35966042d20b14e2d83330049f77deec5229749 ]
Add validation for format string parameters in the firmware tracer to prevent potential security vulnerabilities and crashes from malformed format strings received from firmware.
The firmware tracer receives format strings from the device firmware and uses them to format trace messages. Without proper validation, bad firmware could provide format strings with invalid format specifiers (e.g., %s, %p, %n) that could lead to crashes, or other undefined behavior.
Add mlx5_tracer_validate_params() to validate that all format specifiers in trace strings are limited to safe integer/hex formats (%x, %d, %i, %u, %llx, %lx, etc.). Reject strings containing other format types that could be used to access arbitrary memory or cause crashes. Invalid format strings are added to the trace output for visibility with "BAD_FORMAT: " prefix.
Fixes: 70dd6fdb8987 ("net/mlx5: FW tracer, parse traces and kernel tracing support") Signed-off-by: Shay Drory shayd@nvidia.com Reviewed-by: Moshe Shemesh moshe@nvidia.com Reported-by: Breno Leitao leitao@debian.org Closes: https://lore.kernel.org/netdev/hanz6rzrb2bqbplryjrakvkbmv4y5jlmtthnvi3thg5sl... Signed-off-by: Tariq Toukan tariqt@nvidia.com Link: https://patch.msgid.link/1765284977-1363052-4-git-send-email-tariqt@nvidia.c... Signed-off-by: Paolo Abeni pabeni@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- .../mellanox/mlx5/core/diag/fw_tracer.c | 83 ++++++++++++++++--- .../mellanox/mlx5/core/diag/fw_tracer.h | 1 + 2 files changed, 74 insertions(+), 10 deletions(-)
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 85d3bfa0780c6..197c306d350bf 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/diag/fw_tracer.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/diag/fw_tracer.c @@ -33,6 +33,7 @@ #include "lib/eq.h" #include "fw_tracer.h" #include "fw_tracer_tracepoint.h" +#include <linux/ctype.h>
static int mlx5_query_mtrc_caps(struct mlx5_fw_tracer *tracer) { @@ -358,6 +359,43 @@ static const char *VAL_PARM = "%llx"; static const char *REPLACE_64_VAL_PARM = "%x%x"; static const char *PARAM_CHAR = "%";
+static bool mlx5_is_valid_spec(const char *str) +{ + /* Parse format specifiers to find the actual type. + * Structure: %[flags][width][.precision][length]type + * Skip flags, width, precision & length. + */ + while (isdigit(*str) || *str == '#' || *str == '.' || *str == 'l') + str++; + + /* Check if it's a valid integer/hex specifier: + * Valid formats: %x, %d, %i, %u, etc. + */ + if (*str != 'x' && *str != 'X' && *str != 'd' && *str != 'i' && + *str != 'u' && *str != 'c') + return false; + + return true; +} + +static bool mlx5_tracer_validate_params(const char *str) +{ + const char *substr = str; + + if (!str) + return false; + + substr = strstr(substr, PARAM_CHAR); + while (substr) { + if (!mlx5_is_valid_spec(substr + 1)) + return false; + + substr = strstr(substr + 1, PARAM_CHAR); + } + + return true; +} + static int mlx5_tracer_message_hash(u32 message_id) { return jhash_1word(message_id, 0) & (MESSAGE_HASH_SIZE - 1); @@ -419,6 +457,10 @@ static int mlx5_tracer_get_num_of_params(char *str) char *substr, *pstr = str; int num_of_params = 0;
+ /* Validate that all parameters are valid before processing */ + if (!mlx5_tracer_validate_params(str)) + return -EINVAL; + /* replace %llx with %x%x */ substr = strstr(pstr, VAL_PARM); while (substr) { @@ -570,14 +612,17 @@ void mlx5_tracer_print_trace(struct tracer_string_format *str_frmt, { char tmp[512];
- snprintf(tmp, sizeof(tmp), str_frmt->string, - str_frmt->params[0], - str_frmt->params[1], - str_frmt->params[2], - str_frmt->params[3], - str_frmt->params[4], - str_frmt->params[5], - str_frmt->params[6]); + if (str_frmt->invalid_string) + snprintf(tmp, sizeof(tmp), "BAD_FORMAT: %s", str_frmt->string); + else + snprintf(tmp, sizeof(tmp), str_frmt->string, + str_frmt->params[0], + str_frmt->params[1], + str_frmt->params[2], + str_frmt->params[3], + str_frmt->params[4], + str_frmt->params[5], + str_frmt->params[6]);
trace_mlx5_fw(dev->tracer, trace_timestamp, str_frmt->lost, str_frmt->event_id, tmp); @@ -609,6 +654,13 @@ static int mlx5_tracer_handle_raw_string(struct mlx5_fw_tracer *tracer, return 0; }
+static void mlx5_tracer_handle_bad_format_string(struct mlx5_fw_tracer *tracer, + struct tracer_string_format *cur_string) +{ + cur_string->invalid_string = true; + list_add_tail(&cur_string->list, &tracer->ready_strings_list); +} + static int mlx5_tracer_handle_string_trace(struct mlx5_fw_tracer *tracer, struct tracer_event *tracer_event) { @@ -619,12 +671,18 @@ static int mlx5_tracer_handle_string_trace(struct mlx5_fw_tracer *tracer, if (!cur_string) return mlx5_tracer_handle_raw_string(tracer, tracer_event);
- cur_string->num_of_params = mlx5_tracer_get_num_of_params(cur_string->string); - cur_string->last_param_num = 0; cur_string->event_id = tracer_event->event_id; cur_string->tmsn = tracer_event->string_event.tmsn; cur_string->timestamp = tracer_event->string_event.timestamp; cur_string->lost = tracer_event->lost_event; + cur_string->last_param_num = 0; + cur_string->num_of_params = mlx5_tracer_get_num_of_params(cur_string->string); + if (cur_string->num_of_params < 0) { + pr_debug("%s Invalid format string parameters\n", + __func__); + mlx5_tracer_handle_bad_format_string(tracer, cur_string); + return 0; + } if (cur_string->num_of_params == 0) /* trace with no params */ list_add_tail(&cur_string->list, &tracer->ready_strings_list); } else { @@ -634,6 +692,11 @@ static int mlx5_tracer_handle_string_trace(struct mlx5_fw_tracer *tracer, __func__, tracer_event->string_event.tmsn); return mlx5_tracer_handle_raw_string(tracer, tracer_event); } + if (cur_string->num_of_params < 0) { + pr_debug("%s string parameter of invalid string, dumping\n", + __func__); + return 0; + } cur_string->last_param_num += 1; if (cur_string->last_param_num > TRACER_MAX_PARAMS) { pr_debug("%s Number of params exceeds the max (%d)\n", diff --git a/drivers/net/ethernet/mellanox/mlx5/core/diag/fw_tracer.h b/drivers/net/ethernet/mellanox/mlx5/core/diag/fw_tracer.h index 5c548bb74f07b..30d0bcba88479 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/diag/fw_tracer.h +++ b/drivers/net/ethernet/mellanox/mlx5/core/diag/fw_tracer.h @@ -125,6 +125,7 @@ struct tracer_string_format { struct list_head list; u32 timestamp; bool lost; + bool invalid_string; };
enum mlx5_fw_tracer_ownership_state {