Re: [PATCH] security/loadpin: Replace "kernel_read_file_str[j]" with function "kernel_read_file_id_str(j)".
From: Kees Cook <hidden>
Date: 2021-03-04 23:50:35
Also in:
lkml
On Thu, Mar 04, 2021 at 08:36:38AM +0000, zhaojiele wrote:
quoted hunk ↗ jump to hunk
Actually Linux kernel already provide function "kernel_read_file_id_str()" for secure access in "kernel_read_file.h".And, in "parse_exclude()" function, there is no need for "BUILD_BUG_ON(ARRAY_SIZE(kernel_read_file_str) < ARRAY_SIZE(ignore_read_file_id))" when access array by functon "kernel_read_file_id_str(j)". Signed-off-by: zhaojiele <redacted> --- security/loadpin/loadpin.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-)diff --git a/security/loadpin/loadpin.c b/security/loadpin/loadpin.c index b12f7d986b1e..3e8bdcd06600 100644 --- a/security/loadpin/loadpin.c +++ b/security/loadpin/loadpin.c@@ -210,8 +210,6 @@ static void __init parse_exclude(void) */ BUILD_BUG_ON(ARRAY_SIZE(exclude_read_files) != ARRAY_SIZE(ignore_read_file_id)); - BUILD_BUG_ON(ARRAY_SIZE(kernel_read_file_str) < - ARRAY_SIZE(ignore_read_file_id));
This should stay to make sure kernel_read_file_str doesn't diverge from the other two. However, maybe it should be tightened to: BUILD_BUG_ON(ARRAY_SIZE(kernel_read_file_str) - 1 == ARRAY_SIZE(ignore_read_file_id));
quoted hunk ↗ jump to hunk
for (i = 0; i < ARRAY_SIZE(exclude_read_files); i++) { cur = exclude_read_files[i];@@ -221,9 +219,9 @@ static void __init parse_exclude(void) continue; for (j = 0; j < ARRAY_SIZE(ignore_read_file_id); j++) { - if (strcmp(cur, kernel_read_file_str[j]) == 0) { + if (strcmp(cur, kernel_read_file_id_str(j)) == 0) { pr_info("excluding: %s\n", - kernel_read_file_str[j]); + kernel_read_file_id_str(j)); ignore_read_file_id[j] = 1; /* * Can not break, because one read_file_str
I feel funny about making these into function calls when we've already validated the index, but yeah, that would be fine. Can you send a v2 with the earlier suggestion addressed? Thanks! -Kees -- Kees Cook