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tools/power x86_energy_perf_policy: Fix potential NULL pointer dereference

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In err_on_hypervisor(), strstr() is called to search for "flags" in the
buffer, but the return value is not checked before being used in pointer
arithmetic (flags - buffer). If strstr() returns NULL because "flags" is
not found in /proc/cpuinfo, this will cause undefined behavior and likely
a crash.

Add a NULL check after the strstr() call and handle the error appropriately
by cleaning up resources and reporting a meaningful error message.

Signed-off-by: Malaya Kumar Rout <mrout@redhat.com>
Signed-off-by: Len Brown <len.brown@intel.com>
This commit is contained in:
Malaya Kumar Rout
2025-11-22 20:46:52 +05:30
committed by Len Brown
parent 7446bd6119
commit 51860d6330
1 changed files with 6 additions and 1 deletions
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7
tools/power/x86/x86_energy_perf_policy/x86_energy_perf_policy.c
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@@ -520,7 +520,7 @@ void for_packages(unsigned long long pkg_set, int (func)(int))
void print_version(void) void print_version(void)
{ {
printf("x86_energy_perf_policy 2025.9.19 Len Brown <lenb@kernel.org>\n"); printf("x86_energy_perf_policy 2025.11.22 Len Brown <lenb@kernel.org>\n");
} }
void cmdline(int argc, char **argv) void cmdline(int argc, char **argv)
@@ -662,6 +662,11 @@ void err_on_hypervisor(void)
} }
flags = strstr(buffer, "flags"); flags = strstr(buffer, "flags");
if (!flags) {
fclose(cpuinfo);
free(buffer);
err(1, "Failed to find 'flags' in /proc/cpuinfo");
}
rewind(cpuinfo); rewind(cpuinfo);
fseek(cpuinfo, flags - buffer, SEEK_SET); fseek(cpuinfo, flags - buffer, SEEK_SET);
if (!fgets(buffer, 4096, cpuinfo)) { if (!fgets(buffer, 4096, cpuinfo)) {