From: Pengpeng Hou <pengpeng@iscas.ac.cn> stable inclusion from stable-v6.6.145 commit 0c584c27f6649a93ec12061cc779a4bd8f7c1434 category: bugfix bugzilla: https://atomgit.com/openeuler/kernel/issues/9691 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit f07883450eb14d1cf020b55d9f3a7ec5683bcd26 ] The synthetic field helpers build a prefixed synthetic variable name and a generated hist command in fixed MAX_FILTER_STR_VAL buffers. The current code appends those strings with raw strcat(), so long key lists, field names, or saved filters can run past the end of the staging buffers. Build both strings with seq_buf and propagate -E2BIG if either the synthetic variable name or the generated command exceeds MAX_FILTER_STR_VAL. This keeps the existing tracing-side limit while using the helper intended for bounded command construction. Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Tom Zanussi <tom.zanussi@linux.intel.com> Link: https://patch.msgid.link/20260430043350.57928-1-pengpeng@iscas.ac.cn Fixes: 02205a6752f2 ("tracing: Add support for 'field variables'") Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Reviewed-by: Tom Zanussi <zanussi@kernel.org> Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn> [ sdr: Moved struct seq_buf *s for upside-down x-mas tree formatting ] Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Tengda Wu <wutengda2@huawei.com> --- kernel/trace/trace_events_hist.c | 41 ++++++++++++++++++++++---------- 1 file changed, 29 insertions(+), 12 deletions(-) diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index 78dd8a7ce221..a5fe1776d2a9 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -8,6 +8,7 @@ #include <linux/module.h> #include <linux/kallsyms.h> #include <linux/security.h> +#include <linux/seq_buf.h> #include <linux/mutex.h> #include <linux/slab.h> #include <linux/stacktrace.h> @@ -2947,13 +2948,22 @@ find_synthetic_field_var(struct hist_trigger_data *target_hist_data, { struct hist_field *event_var; char *synthetic_name; + struct seq_buf s; synthetic_name = kzalloc(MAX_FILTER_STR_VAL, GFP_KERNEL); if (!synthetic_name) return ERR_PTR(-ENOMEM); - strcpy(synthetic_name, "synthetic_"); - strcat(synthetic_name, field_name); + seq_buf_init(&s, synthetic_name, MAX_FILTER_STR_VAL); + seq_buf_printf(&s, "synthetic_%s", field_name); + + /* Terminate synthetic_name with a NUL. */ + seq_buf_str(&s); + + if (seq_buf_has_overflowed(&s)) { + kfree(synthetic_name); + return ERR_PTR(-E2BIG); + } event_var = find_event_var(target_hist_data, system, event_name, synthetic_name); @@ -2999,6 +3009,7 @@ create_field_var_hist(struct hist_trigger_data *target_hist_data, struct hist_field *key_field; struct hist_field *event_var; char *saved_filter; + struct seq_buf s; char *cmd; int ret; @@ -3043,28 +3054,34 @@ create_field_var_hist(struct hist_trigger_data *target_hist_data, return ERR_PTR(-ENOMEM); } + seq_buf_init(&s, cmd, MAX_FILTER_STR_VAL); + /* Use the same keys as the compatible histogram */ - strcat(cmd, "keys="); + seq_buf_puts(&s, "keys="); for_each_hist_key_field(i, hist_data) { key_field = hist_data->fields[i]; if (!first) - strcat(cmd, ","); - strcat(cmd, key_field->field->name); + seq_buf_putc(&s, ','); + seq_buf_puts(&s, key_field->field->name); first = false; } /* Create the synthetic field variable specification */ - strcat(cmd, ":synthetic_"); - strcat(cmd, field_name); - strcat(cmd, "="); - strcat(cmd, field_name); + seq_buf_printf(&s, ":synthetic_%s=%s", field_name, field_name); /* Use the same filter as the compatible histogram */ saved_filter = find_trigger_filter(hist_data, file); - if (saved_filter) { - strcat(cmd, " if "); - strcat(cmd, saved_filter); + if (saved_filter) + seq_buf_printf(&s, " if %s", saved_filter); + + /* Terminate cmd with a NUL. */ + seq_buf_str(&s); + + if (seq_buf_has_overflowed(&s)) { + kfree(cmd); + kfree(var_hist); + return ERR_PTR(-E2BIG); } var_hist->cmd = kstrdup(cmd, GFP_KERNEL); -- 2.34.1