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@xxxxxxxxx>
---
cache.h | 1 +
setup.c | 8 ++++++++
2 files changed, 9 insertions(+)
diff --git a/cache.h b/cache.h
index 54c902b..7c8abcb 100644
--- a/cache.h
+++ b/cache.h
@@ -452,6 +452,7 @@ extern const char *get_git_work_tree(void);
#define READ_GITFILE_ERR_NO_PATH 6
#define READ_GITFILE_ERR_CANT_VERIFY_PATH 7
#define READ_GITFILE_ERR_NOT_A_REPO 8
+#define READ_GITFILE_ERR_TOO_LARGE 9
extern const char *read_gitfile_gently(const char *path, int *return_error_code);
#define read_gitfile(path) read_gitfile_gently((path), NULL)
extern const char *resolve_gitdir(const char *suspect);
diff --git a/setup.c b/setup.c
index b919ea6..bfaf4a6 100644
--- a/setup.c
+++ b/setup.c
@@ -381,6 +381,7 @@ static int check_repository_format_gently(const char *gitdir, int *nongit_ok)
*/
const char *read_gitfile_gently(const char *path, int *return_error_code)
{
+ static const int one_MB = 1 << 20;
int error_code = 0;
char *buf = NULL;
char *dir = NULL;
@@ -404,6 +405,11 @@ const char *read_gitfile_gently(const char *path, int *return_error_code)
error_code = READ_GITFILE_ERR_OPEN_FAILED;
goto cleanup_return;
}
+ if (st.st_size > one_MB) {
+ close(fd);
+ error_code = READ_GITFILE_ERR_TOO_LARGE;
+ goto cleanup_return;
+ }
buf = xmalloc(st.st_size + 1);
len = read_in_full(fd, buf, st.st_size);
close(fd);
@@ -463,6 +469,8 @@ cleanup_return:
return NULL;
case READ_GITFILE_ERR_OPEN_FAILED:
die_errno("Error opening '%s'", path);
+ case READ_GITFILE_ERR_TOO_LARGE:
+ die("Too large to be a .git file: '%s'", path);
case READ_GITFILE_ERR_READ_FAILED:
die("Error reading %s", path);
case READ_GITFILE_ERR_INVALID_FORMAT:
--
2.4.0.60.gf7143f7
--
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