From 94ba4f2c33f42dae7813dc169a177e922a39560c Mon Sep 17 00:00:00 2001 From: Benjamin Gray Date: Mon, 28 Nov 2022 15:19:43 +1100 Subject: [PATCH] selftests/powerpc: Add ptrace setup_core_pattern() null-terminator - malloc() does not zero the buffer, - fread() does not null-terminate it's output, - `cat /proc/sys/kernel/core_pattern | hexdump -C` shows the file is not inherently null-terminated So using string operations on the buffer is risky. Explicitly add a null character to the end to make it safer. Signed-off-by: Benjamin Gray Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20221128041948.58339-3-bgray@linux.ibm.com --- tools/testing/selftests/powerpc/ptrace/core-pkey.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/powerpc/ptrace/core-pkey.c b/tools/testing/selftests/powerpc/ptrace/core-pkey.c index 1a70a96..4e8d0ce 100644 --- a/tools/testing/selftests/powerpc/ptrace/core-pkey.c +++ b/tools/testing/selftests/powerpc/ptrace/core-pkey.c @@ -383,7 +383,7 @@ static int setup_core_pattern(char **core_pattern_, bool *changed_) goto out; } - ret = fread(core_pattern, 1, PATH_MAX, f); + ret = fread(core_pattern, 1, PATH_MAX - 1, f); fclose(f); if (!ret) { perror("Error reading core_pattern file"); @@ -391,6 +391,8 @@ static int setup_core_pattern(char **core_pattern_, bool *changed_) goto out; } + core_pattern[ret] = '\0'; + /* Check whether we can predict the name of the core file. */ if (!strcmp(core_pattern, "core") || !strcmp(core_pattern, "core.%p")) *changed_ = false; -- 2.7.4