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authorDavid Oberhollenzer <david.oberhollenzer@sigma-star.at>2020-09-03 17:51:06 +0200
committerDavid Oberhollenzer <david.oberhollenzer@sigma-star.at>2020-09-03 18:28:09 +0200
commitc6d289ab9e604369c25ed2c766842318f74e9256 (patch)
tree9782addc35fcb9c9f85f9c1e7ac79bacbcdb4843
parent4c053b734cc6645ee75a11dd323bd777165d4782 (diff)
Fix integer bounds checking in GNU tar sparse format 1.0 parser
- Make sure the file actually has that many records before trying to read one and fail if not. - Use the helper macros for size_t overflow checking instead of assuming size_t == uint64_t. - Impose a "reasonable" upper bound on the number of data segments and insist that there is at least one entry. Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
-rw-r--r--lib/tar/internal.h1
-rw-r--r--lib/tar/read_sparse_map_new.c14
2 files changed, 13 insertions, 2 deletions
diff --git a/lib/tar/internal.h b/lib/tar/internal.h
index 65e5d45..bea863d 100644
--- a/lib/tar/internal.h
+++ b/lib/tar/internal.h
@@ -42,6 +42,7 @@ enum {
#define TAR_MAX_SYMLINK_LEN (65536)
#define TAR_MAX_PATH_LEN (65536)
#define TAR_MAX_PAX_LEN (65536)
+#define TAR_MAX_SPARSE_ENT (65536)
int read_octal(const char *str, int digits, sqfs_u64 *out);
diff --git a/lib/tar/read_sparse_map_new.c b/lib/tar/read_sparse_map_new.c
index 246f8a5..f4f0f92 100644
--- a/lib/tar/read_sparse_map_new.c
+++ b/lib/tar/read_sparse_map_new.c
@@ -15,9 +15,10 @@ static int decode(const char *str, size_t len, size_t *out)
*out = 0;
while (count < len && isdigit(*str)) {
- if (*out > 0xFFFFFFFFFFFFFFFFUL / 10)
+ if (SZ_MUL_OV(*out, 10, out))
+ return -1;
+ if (SZ_ADD_OV(*out, (*(str++) - '0'), out))
return -1;
- *out = (*out) * 10 + (*(str++) - '0');
++count;
}
@@ -34,6 +35,9 @@ sparse_map_t *read_gnu_new_sparse(FILE *fp, tar_header_decoded_t *out)
char buffer[1024];
int diff, ret;
+ if (out->record_size < 512)
+ goto fail_format;
+
if (read_retry("reading GNU sparse map", fp, buffer, 512))
return NULL;
@@ -43,6 +47,9 @@ sparse_map_t *read_gnu_new_sparse(FILE *fp, tar_header_decoded_t *out)
out->record_size -= 512;
+ if (count == 0 || count > TAR_MAX_SPARSE_ENT)
+ goto fail_format;
+
for (i = 0; i < (count * 2); ++i) {
ret = decode(buffer + diff, 512 - diff, &value);
if (ret < 0)
@@ -51,6 +58,9 @@ sparse_map_t *read_gnu_new_sparse(FILE *fp, tar_header_decoded_t *out)
if (ret > 0) {
diff += ret;
} else {
+ if (out->record_size < 512)
+ goto fail_format;
+
if (read_retry("reading GNU sparse map", fp,
buffer + 512, 512)) {
return NULL;