[PATCH v6 3/7] setup: sanity check file size in read_gitfile_gently
From: Erik Elfström <hidden>
Date: 2016-06-15 23:04:42
Subsystem:
the rest · Maintainer:
Linus Torvalds
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 <redacted> --- 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