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authorBenjamin Gray <bgray@linux.ibm.com>2023-03-20 15:08:38 +1100
committerMasahiro Yamada <masahiroy@kernel.org>2023-04-16 17:37:01 +0900
commit5efb685bb3af112038af78a2cdf28f0ffdad45f5 (patch)
tree49ea55e7ce2803846e6399e0ccc6d09e3a7bb64d /usr
parentaa7d233f45b4c549750044c9921f7afcbe50925b (diff)
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initramfs: Check negative timestamp to prevent broken cpio archive
Similar to commit 4c9d410f32b3 ("initramfs: Check timestamp to prevent broken cpio archive"), except asserts that the timestamp is non-negative. This can happen when the KBUILD_BUILD_TIMESTAMP is a value before UNIX epoch, which may be set when making reproducible builds that don't want to look like they use a valid date. While support for dates before 1970 might not be supported, this is more about preventing undetected CPIO corruption. The printf's use a minimum length format specifier, and will happily make the field longer than 8 characters if they need to. Signed-off-by: Benjamin Gray <bgray@linux.ibm.com> Reviewed-by: Andrew Donnellan <ajd@linux.ibm.com> Tested-by: Andrew Donnellan <ajd@linux.ibm.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Diffstat (limited to 'usr')
-rw-r--r--usr/gen_init_cpio.c12
1 files changed, 9 insertions, 3 deletions
diff --git a/usr/gen_init_cpio.c b/usr/gen_init_cpio.c
index ee01e40e8bc6..61230532fef1 100644
--- a/usr/gen_init_cpio.c
+++ b/usr/gen_init_cpio.c
@@ -353,6 +353,12 @@ static int cpio_mkfile(const char *name, const char *location,
buf.st_mtime = 0xffffffff;
}
+ if (buf.st_mtime < 0) {
+ fprintf(stderr, "%s: Timestamp negative, clipping.\n",
+ location);
+ buf.st_mtime = 0;
+ }
+
if (buf.st_size > 0xffffffff) {
fprintf(stderr, "%s: Size exceeds maximum cpio file size\n",
location);
@@ -602,10 +608,10 @@ int main (int argc, char *argv[])
/*
* Timestamps after 2106-02-07 06:28:15 UTC have an ascii hex time_t
* representation that exceeds 8 chars and breaks the cpio header
- * specification.
+ * specification. Negative timestamps similarly exceed 8 chars.
*/
- if (default_mtime > 0xffffffff) {
- fprintf(stderr, "ERROR: Timestamp too large for cpio format\n");
+ if (default_mtime > 0xffffffff || default_mtime < 0) {
+ fprintf(stderr, "ERROR: Timestamp out of range for cpio format\n");
exit(1);
}