tar: skip leading / and handle names like abc/..////def -> def (not ///def)

function                                             old     new   delta
strip_unsafe_prefix                                    -     105    +105
writeFileToTarball                                   557     520     -37
get_header_tar                                      1545    1462     -83

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

4 files changed, 59 insertions, 59 deletions

diff --git a/archival/libarchive/get_header_tar.c b/archival/libarchive/get_header_tar.c
index 6a1532c86..f73cd338e 100644
--- a/archival/libarchive/get_header_tar.c
+++ b/archival/libarchive/get_header_tar.c
@@ -18,6 +18,35 @@ typedef uint32_t aliased_uint32_t FIX_ALIASING;
 typedef off_t    aliased_off_t    FIX_ALIASING;
 
 
+const char* FAST_FUNC strip_unsafe_prefix(const char *str)
+{
+	const char *cp = str;
+	while (1) {
+		char *cp2;
+		if (*cp == '/') {
+			cp++;
+			continue;
+		}
+		if (strncmp(cp, "/../"+1, 3) == 0) {
+			cp += 3;
+			continue;
+		}
+		cp2 = strstr(cp, "/../");
+		if (!cp2)
+			break;
+		cp = cp2 + 4;
+	}
+	if (cp != str) {
+		static smallint warned = 0;
+		if (!warned) {
+			warned = 1;
+			bb_error_msg("removing leading '%.*s' from member names",
+				(int)(cp - str), str);
+		}
+	}
+	return cp;
+}
+
 /* NB: _DESTROYS_ str[len] character! */
 static unsigned long long getOctal(char *str, int len)
 {
@@ -424,27 +453,7 @@ char FAST_FUNC get_header_tar(archive_handle_t *archive_handle)
 #endif
 
 	/* Everything up to and including last ".." component is stripped */
-	cp = file_header->name;
-	while (1) {
-		char *cp2;
-		if (strncmp(cp, "/../"+1, 3) == 0) {
-			cp += 3;
-			continue;
-		}
-		cp2 = strstr(cp, "/../");
-		if (cp2) {
-			cp = cp2 + 4;
-			continue;
-		}
-		break;
-	}
-	if (cp != file_header->name) {
-		if (!(archive_handle->ah_flags & ARCHIVE_TAR__TRUNC_WARNED)) {
-			archive_handle->ah_flags |= ARCHIVE_TAR__TRUNC_WARNED;
-			bb_error_msg("removing leading '%.*s'", (int)(cp - file_header->name), file_header->name);
-		}
-		overlapping_strcpy(file_header->name, cp);
-	}
+	overlapping_strcpy(file_header->name, strip_unsafe_prefix(file_header->name));
 
 	/* Strip trailing '/' in directories */
 	/* Must be done after mode is set as '/' is used to check if it's a directory */
diff --git a/archival/tar.c b/archival/tar.c
index 1e3cecf44..d43c8dee3 100644
--- a/archival/tar.c
+++ b/archival/tar.c
@@ -397,17 +397,8 @@ static int FAST_FUNC writeFileToTarball(const char *fileName, struct stat *statb
 
 	DBG("writeFileToTarball('%s')", fileName);
 
-	/* Strip leading '/' (must be before memorizing hardlink's name) */
-	header_name = fileName;
-	while (header_name[0] == '/') {
-		static smallint warned;
-
-		if (!warned) {
-			bb_error_msg("removing leading '/' from member names");
-			warned = 1;
-		}
-		header_name++;
-	}
+	/* Strip leading '/' and such (must be before memorizing hardlink's name) */
+	header_name = strip_unsafe_prefix(fileName);
 
 	if (header_name[0] == '\0')
 		return TRUE;
diff --git a/include/archive.h b/include/archive.h
index 9fc77e542..181c187f7 100644
--- a/include/archive.h
+++ b/include/archive.h
@@ -118,8 +118,6 @@ typedef struct archive_handle_t {
 #define ARCHIVE_DONT_RESTORE_PERM   (1 << 6)
 #define ARCHIVE_NUMERIC_OWNER       (1 << 7)
 #define ARCHIVE_O_TRUNC             (1 << 8)
-/* Archiver specific. */
-#define ARCHIVE_TAR__TRUNC_WARNED   (1 << 9)
 
 
 /* POSIX tar Header Block, from POSIX 1003.1-1990  */
@@ -161,37 +159,39 @@ typedef struct unpack_info_t {
 	time_t mtime;
 } unpack_info_t;
 
-extern archive_handle_t *init_handle(void) FAST_FUNC;
+archive_handle_t *init_handle(void) FAST_FUNC;
 
-extern char filter_accept_all(archive_handle_t *archive_handle) FAST_FUNC;
-extern char filter_accept_list(archive_handle_t *archive_handle) FAST_FUNC;
-extern char filter_accept_list_reassign(archive_handle_t *archive_handle) FAST_FUNC;
-extern char filter_accept_reject_list(archive_handle_t *archive_handle) FAST_FUNC;
+char filter_accept_all(archive_handle_t *archive_handle) FAST_FUNC;
+char filter_accept_list(archive_handle_t *archive_handle) FAST_FUNC;
+char filter_accept_list_reassign(archive_handle_t *archive_handle) FAST_FUNC;
+char filter_accept_reject_list(archive_handle_t *archive_handle) FAST_FUNC;
 
-extern void unpack_ar_archive(archive_handle_t *ar_archive) FAST_FUNC;
+void unpack_ar_archive(archive_handle_t *ar_archive) FAST_FUNC;
 
-extern void data_skip(archive_handle_t *archive_handle) FAST_FUNC;
-extern void data_extract_all(archive_handle_t *archive_handle) FAST_FUNC;
-extern void data_extract_to_stdout(archive_handle_t *archive_handle) FAST_FUNC;
-extern void data_extract_to_command(archive_handle_t *archive_handle) FAST_FUNC;
+void data_skip(archive_handle_t *archive_handle) FAST_FUNC;
+void data_extract_all(archive_handle_t *archive_handle) FAST_FUNC;
+void data_extract_to_stdout(archive_handle_t *archive_handle) FAST_FUNC;
+void data_extract_to_command(archive_handle_t *archive_handle) FAST_FUNC;
 
-extern void header_skip(const file_header_t *file_header) FAST_FUNC;
-extern void header_list(const file_header_t *file_header) FAST_FUNC;
-extern void header_verbose_list(const file_header_t *file_header) FAST_FUNC;
+void header_skip(const file_header_t *file_header) FAST_FUNC;
+void header_list(const file_header_t *file_header) FAST_FUNC;
+void header_verbose_list(const file_header_t *file_header) FAST_FUNC;
 
-extern char get_header_ar(archive_handle_t *archive_handle) FAST_FUNC;
-extern char get_header_cpio(archive_handle_t *archive_handle) FAST_FUNC;
-extern char get_header_tar(archive_handle_t *archive_handle) FAST_FUNC;
-extern char get_header_tar_gz(archive_handle_t *archive_handle) FAST_FUNC;
-extern char get_header_tar_bz2(archive_handle_t *archive_handle) FAST_FUNC;
-extern char get_header_tar_lzma(archive_handle_t *archive_handle) FAST_FUNC;
+char get_header_ar(archive_handle_t *archive_handle) FAST_FUNC;
+char get_header_cpio(archive_handle_t *archive_handle) FAST_FUNC;
+char get_header_tar(archive_handle_t *archive_handle) FAST_FUNC;
+char get_header_tar_gz(archive_handle_t *archive_handle) FAST_FUNC;
+char get_header_tar_bz2(archive_handle_t *archive_handle) FAST_FUNC;
+char get_header_tar_lzma(archive_handle_t *archive_handle) FAST_FUNC;
 
-extern void seek_by_jump(int fd, off_t amount) FAST_FUNC;
-extern void seek_by_read(int fd, off_t amount) FAST_FUNC;
+void seek_by_jump(int fd, off_t amount) FAST_FUNC;
+void seek_by_read(int fd, off_t amount) FAST_FUNC;
 
-extern void data_align(archive_handle_t *archive_handle, unsigned boundary) FAST_FUNC;
-extern const llist_t *find_list_entry(const llist_t *list, const char *filename) FAST_FUNC;
-extern const llist_t *find_list_entry2(const llist_t *list, const char *filename) FAST_FUNC;
+const char *strip_unsafe_prefix(const char *str) FAST_FUNC;
+
+void data_align(archive_handle_t *archive_handle, unsigned boundary) FAST_FUNC;
+const llist_t *find_list_entry(const llist_t *list, const char *filename) FAST_FUNC;
+const llist_t *find_list_entry2(const llist_t *list, const char *filename) FAST_FUNC;
 
 /* A bit of bunzip2 internals are exposed for compressed help support: */
 typedef struct bunzip_data bunzip_data;
diff --git a/testsuite/tar.tests b/testsuite/tar.tests
index d41d10d57..534135df8 100755
--- a/testsuite/tar.tests
+++ b/testsuite/tar.tests
@@ -178,7 +178,7 @@ rm -rf input_* 2>/dev/null
 tar -vxf test.tar 2>&1
 cat input_dir/file 2>&1
 " "\
-tar: removing leading './../tar.tempdir/input_dir/../'
+tar: removing leading './../tar.tempdir/input_dir/../' from member names
 input_dir/
 input_dir/file
 Ok