github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-07-28 10:09:10 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph

perf hwmon: Fix off-by-one null termination on sysfs reads

Browse Source 
Three functions read sysfs files into fixed-size stack buffers using
the full buffer size, then null-terminate at buf[read_len].  If the
read fills the buffer exactly, read_len equals sizeof(buf) and the
null byte writes one past the array, corrupting an adjacent stack
variable.

Fix all three by reading sizeof(buf) - 1 bytes, reserving space for
the null terminator:

  - hwmon_pmu__read_events(): buf[128]
  - hwmon_pmu__describe_items(): buf[64]
  - evsel__hwmon_pmu_read(): buf[32]

Fixes: 53cc0b351e ("perf hwmon_pmu: Add a tool PMU exposing events from hwmon in sysfs")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Cc: Ian Rogers <irogers@google.com>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Arnaldo Carvalho de Melo 2026-06-07 22:38:26 -03:00
parent 31d5960545
commit 1847c5fae3
1 changed files with 3 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
tools/perf/util/hwmon_pmu.c
View File

@ -289,7 +289,7 @@ static int hwmon_pmu__read_events(struct hwmon_pmu *pmu)
if (fd < 0)
continue;
read_len = read(fd, buf, sizeof(buf));
read_len = read(fd, buf, sizeof(buf) - 1);
while (read_len > 0 && buf[read_len - 1] == '\n')
read_len--;
@ -432,7 +432,7 @@ static size_t hwmon_pmu__describe_items(struct hwmon_pmu *hwm, char *out_buf, si
is_alarm ? "_alarm" : "");
fd = openat(dir, buf, O_RDONLY);
if (fd > 0) {
ssize_t read_len = read(fd, buf, sizeof(buf));
ssize_t read_len = read(fd, buf, sizeof(buf) - 1);
while (read_len > 0 && buf[read_len - 1] == '\n')
read_len--;
@ -816,7 +816,7 @@ int evsel__hwmon_pmu_read(struct evsel *evsel, int cpu_map_idx, int thread)
count = perf_counts(evsel->counts, cpu_map_idx, thread);
fd = FD(evsel, cpu_map_idx, thread);
len = pread(fd, buf, sizeof(buf), 0);
len = pread(fd, buf, sizeof(buf) - 1, 0);
if (len <= 0) {
count->lost++;
return -EINVAL;