@matheusbsbs / matheus-bagliano / commits / 921bdd96af

setup: sanity check file size in read_gitfile_gently

read_gitfile_gently will allocate a buffer to fit the entire file that should be read. Add a sanity check of the file size before opening to avoid allocating a potentially huge amount of memory if we come across a large file that someone happened to name ".git". The limit is set to a sufficiently unreasonable size that should never be exceeded by a genuine .git file. Signed-off-by: Erik Elfström <erik.elfstrom@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Erik Elfström committed Jun 15, 2015 at 21:39 UTC 921bdd96afc17ca055af261066eabdf026cb2195

2 files changed +8

cache.h

@@ -454,6 +454,7 @@ extern const char *get_git_work_tree(void);

454 #define READ_GITFILE_ERR_INVALID_FORMAT 5

455 #define READ_GITFILE_ERR_NO_PATH 6

456 #define READ_GITFILE_ERR_NOT_A_REPO 7

457 +#define READ_GITFILE_ERR_TOO_LARGE 8

458 extern const char *read_gitfile_gently(const char *path, int *return_error_code);

459 #define read_gitfile(path) read_gitfile_gently((path), NULL)

460 extern const char *resolve_gitdir(const char *suspect);

setup.c

@@ -414,6 +414,7 @@ static void update_linked_gitdir(const char *gitfile, const char *gitdir)

414 */

415 const char *read_gitfile_gently(const char *path, int *return_error_code)

416 {

417 + const int max_file_size = 1 << 20; /* 1MB */

418 int error_code = 0;

419 char *buf = NULL;

420 char *dir = NULL;

@@ -430,6 +431,10 @@ const char *read_gitfile_gently(const char *path, int *return_error_code)

431 error_code = READ_GITFILE_ERR_NOT_A_FILE;

432 goto cleanup_return;

433 }

434 + if (st.st_size > max_file_size) {

435 + error_code = READ_GITFILE_ERR_TOO_LARGE;

436 + goto cleanup_return;

437 + }

438 fd = open(path, O_RDONLY);

439 if (fd < 0) {

440 error_code = READ_GITFILE_ERR_OPEN_FAILED;

@@ -489,6 +494,8 @@ cleanup_return:

494 return NULL;

495 case READ_GITFILE_ERR_OPEN_FAILED:

496 die_errno("Error opening '%s'", path);

497 + case READ_GITFILE_ERR_TOO_LARGE:

498 + die("Too large to be a .git file: '%s'", path);

499 case READ_GITFILE_ERR_READ_FAILED:

500 die("Error reading %s", path);

501 case READ_GITFILE_ERR_INVALID_FORMAT: