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.
Unified · Split
| @@ -353,6 +353,12 @@ static int cpio_mkfile(const char *name, const char *location, · 352 unmodified lines | |||
| 353 | buf.st_mtime = 0xffffffff; | 353 | buf.st_mtime = 0xffffffff; |
| 354 | } | 354 | } |
| 355 | 355 | ||
| 356 | if (buf.st_mtime < 0) { | ||
| 357 | fprintf(stderr, "%s: Timestamp negative, clipping.\n", | ||
| 358 | location); | ||
| 359 | buf.st_mtime = 0; | ||
| 360 | } | ||
| 361 | |||
| 356 | if (buf.st_size > 0xffffffff) { | 362 | if (buf.st_size > 0xffffffff) { |
| 357 | fprintf(stderr, "%s: Size exceeds maximum cpio file size\n", | 363 | fprintf(stderr, "%s: Size exceeds maximum cpio file size\n", |
| 358 | location); | 364 | location); |
| @@ -602,10 +608,10 @@ int main (int argc, char *argv[]) · 243 unmodified lines | |||
| 602 | /* | 608 | /* |
| 603 | * Timestamps after 2106-02-07 06:28:15 UTC have an ascii hex time_t | 609 | * Timestamps after 2106-02-07 06:28:15 UTC have an ascii hex time_t |
| 604 | * representation that exceeds 8 chars and breaks the cpio header | 610 | * representation that exceeds 8 chars and breaks the cpio header |
| 605 | * specification. | 611 | * specification. Negative timestamps similarly exceed 8 chars. |
| 606 | */ | 612 | */ |
| 607 | if (default_mtime > 0xffffffff) { | 613 | if (default_mtime > 0xffffffff || default_mtime < 0) { |
| 608 | fprintf(stderr, "ERROR: Timestamp too large for cpio format\n"); | 614 | fprintf(stderr, "ERROR: Timestamp out of range for cpio format\n"); |
| 609 | exit(1); | 615 | exit(1); |
| 610 | } | 616 | } |
| 611 | 617 | ||