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copy_file: handle "cp /dev/foo file" (almost) compatibly to coreutils.

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(almost because we do not copy mode, which is probably wasn't intended).
+61 bytes.
This commit is contained in:
Denis Vlasenko
2008-03-28 17:49:31 +00:00
parent a38ba59cc3
commit b9ad75fa60
6 changed files with 63 additions and 26 deletions
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37
libbb/copy_file.c
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@@ -81,6 +81,7 @@ int copy_file(const char *source, const char *dest, int flags)
signed char dest_exists = 0;
signed char ovr;
/* Inverse of cp -d ("cp without -d") */
#define FLAGS_DEREF (flags & FILEUTILS_DEREFERENCE)
if ((FLAGS_DEREF ? stat : lstat)(source, &source_stat) < 0) {
@@ -229,12 +230,22 @@ int copy_file(const char *source, const char *dest, int flags)
return 0;
}
if (S_ISREG(source_stat.st_mode)
/* DEREF uses stat, which never returns S_ISLNK() == true. */
if (/* "cp thing1 thing2" without -R: just open and read() from thing1 */
!(flags & FILEUTILS_RECUR)
/* "cp [-opts] regular_file thing2" */
|| S_ISREG(source_stat.st_mode)
/* DEREF uses stat, which never returns S_ISLNK() == true.
* So the below is never true: */
/* || (FLAGS_DEREF && S_ISLNK(source_stat.st_mode)) */
) {
int src_fd;
int dst_fd;
mode_t new_mode;
if (!FLAGS_DEREF && S_ISLNK(source_stat.st_mode)) {
/* "cp -d symlink dst": create a link */
goto dont_cat;
}
if (ENABLE_FEATURE_PRESERVE_HARDLINKS && !FLAGS_DEREF) {
const char *link_target;
@@ -258,18 +269,24 @@ int copy_file(const char *source, const char *dest, int flags)
if (src_fd < 0)
return -1;
/* Do not try to open with weird mode fields */
new_mode = source_stat.st_mode;
if (!S_ISREG(source_stat.st_mode))
new_mode = 0666;
/* POSIX way is a security problem versus symlink attacks,
* we do it only for non-symlinks, and only for non-recursive,
* non-interactive cp. NB: it is still racy
* for "cp file /home/bad_user/file" case
* (user can rm file and create a link to /etc/passwd) */
if (DO_POSIX_CP
|| (dest_exists && !(flags & (FILEUTILS_RECUR|FILEUTILS_INTERACTIVE))
|| (dest_exists
&& !(flags & (FILEUTILS_RECUR|FILEUTILS_INTERACTIVE))
&& !S_ISLNK(dest_stat.st_mode))
) {
dst_fd = open(dest, O_WRONLY|O_CREAT|O_TRUNC, source_stat.st_mode);
dst_fd = open(dest, O_WRONLY|O_CREAT|O_TRUNC, new_mode);
} else /* safe way: */
dst_fd = open(dest, O_WRONLY|O_CREAT|O_EXCL, source_stat.st_mode);
dst_fd = open(dest, O_WRONLY|O_CREAT|O_EXCL, new_mode);
if (dst_fd == -1) {
ovr = ask_and_unlink(dest, flags);
if (ovr <= 0) {
@@ -277,7 +294,7 @@ int copy_file(const char *source, const char *dest, int flags)
return ovr;
}
/* It shouldn't exist. If it exists, do not open (symlink attack?) */
dst_fd = open3_or_warn(dest, O_WRONLY|O_CREAT|O_EXCL, source_stat.st_mode);
dst_fd = open3_or_warn(dest, O_WRONLY|O_CREAT|O_EXCL, new_mode);
if (dst_fd < 0) {
close(src_fd);
return -1;
@@ -285,8 +302,7 @@ int copy_file(const char *source, const char *dest, int flags)
}
#if ENABLE_SELINUX
if (((flags & FILEUTILS_PRESERVE_SECURITY_CONTEXT)
|| (flags & FILEUTILS_SET_SECURITY_CONTEXT))
if ((flags & (FILEUTILS_PRESERVE_SECURITY_CONTEXT|FILEUTILS_SET_SECURITY_CONTEXT))
&& is_selinux_enabled() > 0
) {
security_context_t con;
@@ -313,8 +329,13 @@ int copy_file(const char *source, const char *dest, int flags)
}
/* ...but read size is already checked by bb_copyfd_eof */
close(src_fd);
/* "cp /dev/something new_file" should not
* copy mode of /dev/something */
if (!S_ISREG(source_stat.st_mode))
return retval;
goto preserve_mode_ugid_time;
}
dont_cat:
/* Source is a symlink or a special file */
/* We are lazy here, a bit lax with races... */