8a5fab633
Denis Vlasenko
2007-08-27
Subject
cp: detect and prevent infinite recursion
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Commit Diff GitHub →
libbb/copy_file.c+35 -17
| @@ -114,6 +114,7 @@ int copy_file(const char *source, const char *dest, int flags) | |
| if (S_ISDIR(source_stat.st_mode)) { | |
| DIR *dp; | |
| + | const char *existing_name; |
| struct dirent *d; | |
| mode_t saved_umask = 0; | |
| @@ -122,6 +123,15 @@ int copy_file(const char *source, const char *dest, int flags) | |
| return -1; | |
| } | |
| + | /* Did we ever create source ourself before? */ |
| + | existing_name = is_in_ino_dev_hashtable(&source_stat); |
| + | if (existing_name) { |
| + | /* We did! it's a recursion! man the lifeboats... */ |
| + | bb_error_msg("recursion detected, omitting directory '%s'", |
| + | existing_name); |
| + | return -1; |
| + | } |
| + | |
| /* Create DEST */ | |
| if (dest_exists) { | |
| if (!S_ISDIR(dest_stat.st_mode)) { | |
| @@ -143,7 +153,15 @@ int copy_file(const char *source, const char *dest, int flags) | |
| return -1; | |
| } | |
| umask(saved_umask); | |
| + | /* need stat info for add_to_ino_dev_hashtable */ |
| + | if (lstat(dest, &dest_stat) < 0) { |
| + | bb_perror_msg("cannot stat '%s'", dest); |
| + | return -1; |
| + | } |
| } | |
| + | /* remember (dev,inode) of each created dir. |
| + | * NULL: name is not remembered */ |
| + | add_to_ino_dev_hashtable(&dest_stat, NULL); |
| /* Recursively copy files in SOURCE */ | |
| dp = opendir(source); | |
| @@ -169,8 +187,8 @@ int copy_file(const char *source, const char *dest, int flags) | |
| if (!dest_exists | |
| && chmod(dest, source_stat.st_mode & ~saved_umask) < 0 | |
| ) { | |
| - | bb_perror_msg("cannot change permissions of '%s'", dest); |
| - | retval = -1; |
| + | bb_perror_msg("cannot preserve %s of '%s'", "permissions", dest); |
| + | /* retval = -1; - WRONG! copy *WAS* made */ |
| } | |
| goto preserve_mode_ugid_time; | |
| } | |
| @@ -197,7 +215,7 @@ int copy_file(const char *source, const char *dest, int flags) | |
| } | |
| if (S_ISREG(source_stat.st_mode) | |
| - | /* Huh? DEREF uses stat, which never returns links! */ |
| + | /* DEREF uses stat, which never returns S_ISLNK() == true. */ |
| /* || (FLAGS_DEREF && S_ISLNK(source_stat.st_mode)) */ | |
| ) { | |
| int src_fd; | |
| @@ -269,14 +287,13 @@ int copy_file(const char *source, const char *dest, int flags) | |
| #endif | |
| if (bb_copyfd_eof(src_fd, dst_fd) == -1) | |
| retval = -1; | |
| + | /* Ok, writing side I can understand... */ |
| if (close(dst_fd) < 0) { | |
| bb_perror_msg("cannot close '%s'", dest); | |
| retval = -1; | |
| } | |
| - | if (close(src_fd) < 0) { |
| - | bb_perror_msg("cannot close '%s'", source); |
| - | retval = -1; |
| - | } |
| + | /* ...but read size is already checked by bb_copyfd_eof */ |
| + | close(src_fd); |
| goto preserve_mode_ugid_time; | |
| } | |
| @@ -289,18 +306,18 @@ int copy_file(const char *source, const char *dest, int flags) | |
| return ovr; | |
| } | |
| if (S_ISLNK(source_stat.st_mode)) { | |
| - | char *lpath; |
| - | |
| - | lpath = xmalloc_readlink_or_warn(source); |
| - | if (lpath && symlink(lpath, dest) < 0) { |
| - | bb_perror_msg("cannot create symlink '%s'", dest); |
| + | char *lpath = xmalloc_readlink_or_warn(source); |
| + | if (lpath) { |
| + | int r = symlink(lpath, dest); |
| free(lpath); | |
| - | return -1; |
| + | if (r < 0) { |
| + | bb_perror_msg("cannot create symlink '%s'", dest); |
| + | return -1; |
| + | } |
| + | if (flags & FILEUTILS_PRESERVE_STATUS) |
| + | if (lchown(dest, source_stat.st_uid, source_stat.st_gid) < 0) |
| + | bb_perror_msg("cannot preserve %s of '%s'", "ownership", dest); |
| } | |
| - | free(lpath); |
| - | if (flags & FILEUTILS_PRESERVE_STATUS) |
| - | if (lchown(dest, source_stat.st_uid, source_stat.st_gid) < 0) |
| - | bb_perror_msg("cannot preserve %s of '%s'", "ownership", dest); |
| /* _Not_ jumping to preserve_mode_ugid_time: | |
| * symlinks don't have those */ | |
| return 0; | |
| @@ -327,6 +344,7 @@ int copy_file(const char *source, const char *dest, int flags) | |
| times.actime = source_stat.st_atime; | |
| times.modtime = source_stat.st_mtime; | |
| + | /* BTW, utimes sets usec-precision time - just FYI */ |
| if (utime(dest, ×) < 0) | |
| bb_perror_msg("cannot preserve %s of '%s'", "times", dest); | |
| if (chown(dest, source_stat.st_uid, source_stat.st_gid) < 0) { | |