diff options
| -rw-r--r-- | ChangeLog | 22 | ||||
| -rw-r--r-- | NEWS | 7 | ||||
| -rw-r--r-- | manual/conf.texi | 9 | ||||
| -rw-r--r-- | manual/filesys.texi | 73 | ||||
| -rw-r--r-- | sysdeps/posix/dirstream.h | 2 | ||||
| -rw-r--r-- | sysdeps/posix/opendir.c | 1 | ||||
| -rw-r--r-- | sysdeps/posix/readdir_r.c | 42 | ||||
| -rw-r--r-- | sysdeps/posix/rewinddir.c | 1 | ||||
| -rw-r--r-- | sysdeps/unix/sysv/linux/i386/readdir64_r.c | 1 | ||||
| -rw-r--r-- | sysdeps/unix/sysv/linux/wordsize-64/readdir_r.c | 1 |
10 files changed, 124 insertions, 35 deletions
@@ -1,3 +1,25 @@ +2013-08-16 Florian Weimer <fweimer@redhat.com> + + [BZ #14699] + CVE-2013-4237 + * sysdeps/posix/dirstream.h (struct __dirstream): Add errcode + member. + * sysdeps/posix/opendir.c (__alloc_dir): Initialize errcode + member. + * sysdeps/posix/rewinddir.c (rewinddir): Reset errcode member. + * sysdeps/posix/readdir_r.c (__READDIR_R): Enforce NAME_MAX limit. + Return delayed error code. Remove GETDENTS_64BIT_ALIGNED + conditional. + * sysdeps/unix/sysv/linux/wordsize-64/readdir_r.c: Do not define + GETDENTS_64BIT_ALIGNED. + * sysdeps/unix/sysv/linux/i386/readdir64_r.c: Likewise. + * manual/filesys.texi (Reading/Closing Directory): Document + ENAMETOOLONG return value of readdir_r. Recommend readdir more + strongly. + * manual/conf.texi (Limits for Files): Add portability note to + NAME_MAX, PATH_MAX. + (Pathconf): Add portability note for _PC_NAME_MAX, _PC_PATH_MAX. + 2013-08-13 Andreas Schwab <schwab@suse.de> [BZ #15749] @@ -9,7 +9,12 @@ Version 2.19 * The following bugs are resolved with this release: - 15749 + 14699, 15749 + +* CVE-2013-4237 The readdir_r function could write more than NAME_MAX bytes + to the d_name member of struct dirent, or omit the terminating NUL + character. (Bugzilla #14699). + Version 2.18 diff --git a/manual/conf.texi b/manual/conf.texi index 7eb8b36..c720063 100644 --- a/manual/conf.texi +++ b/manual/conf.texi @@ -1149,6 +1149,9 @@ typed ahead as input. @xref{I/O Queues}. @deftypevr Macro int NAME_MAX The uniform system limit (if any) for the length of a file name component, not including the terminating null character. + +@strong{Portability Note:} On some systems, @theglibc{} defines +@code{NAME_MAX}, but does not actually enforce this limit. @end deftypevr @comment limits.h @@ -1157,6 +1160,9 @@ including the terminating null character. The uniform system limit (if any) for the length of an entire file name (that is, the argument given to system calls such as @code{open}), including the terminating null character. + +@strong{Portability Note:} @Theglibc{} does not enforce this limit +even if @code{PATH_MAX} is defined. @end deftypevr @cindex limits, pipe buffer size @@ -1476,6 +1482,9 @@ Inquire about the value of @code{POSIX_REC_MIN_XFER_SIZE}. Inquire about the value of @code{POSIX_REC_XFER_ALIGN}. @end table +@strong{Portability Note:} On some systems, @theglibc{} does not +enforce @code{_PC_NAME_MAX} or @code{_PC_PATH_MAX} limits. + @node Utility Limits @section Utility Program Capacity Limits diff --git a/manual/filesys.texi b/manual/filesys.texi index 1df9cf2..814c210 100644 --- a/manual/filesys.texi +++ b/manual/filesys.texi @@ -444,9 +444,9 @@ symbols are declared in the header file @file{dirent.h}. @comment POSIX.1 @deftypefun {struct dirent *} readdir (DIR *@var{dirstream}) This function reads the next entry from the directory. It normally -returns a pointer to a structure containing information about the file. -This structure is statically allocated and can be rewritten by a -subsequent call. +returns a pointer to a structure containing information about the +file. This structure is associated with the @var{dirstream} handle +and can be rewritten by a subsequent call. @strong{Portability Note:} On some systems @code{readdir} may not return entries for @file{.} and @file{..}, even though these are always @@ -461,19 +461,61 @@ conditions are defined for this function: The @var{dirstream} argument is not valid. @end table -@code{readdir} is not thread safe. Multiple threads using -@code{readdir} on the same @var{dirstream} may overwrite the return -value. Use @code{readdir_r} when this is critical. +To distinguish between an end-of-directory condition or an error, you +must set @code{errno} to zero before calling @code{readdir}. To avoid +entering an infinite loop, you should stop reading from the directory +after the first error. + +In POSIX.1-2008, @code{readdir} is not thread-safe. In @theglibc{} +implementation, it is safe to call @code{readdir} concurrently on +different @var{dirstream}s, but multiple threads accessing the same +@var{dirstream} result in undefined behavior. @code{readdir_r} is a +fully thread-safe alternative, but suffers from poor portability (see +below). It is recommended that you use @code{readdir}, with external +locking if multiple threads access the same @var{dirstream}. @end deftypefun @comment dirent.h @comment GNU @deftypefun int readdir_r (DIR *@var{dirstream}, struct dirent *@var{entry}, struct dirent **@var{result}) -This function is the reentrant version of @code{readdir}. Like -@code{readdir} it returns the next entry from the directory. But to -prevent conflicts between simultaneously running threads the result is -not stored in statically allocated memory. Instead the argument -@var{entry} points to a place to store the result. +This function is a version of @code{readdir} which performs internal +locking. Like @code{readdir} it returns the next entry from the +directory. To prevent conflicts between simultaneously running +threads the result is stored inside the @var{entry} object. + +@strong{Portability Note:} It is recommended to use @code{readdir} +instead of @code{readdir_r} for the following reasons: + +@itemize @bullet +@item +On systems which do not define @code{NAME_MAX}, it may not be possible +to use @code{readdir_r} safely because the caller does not specify the +length of the buffer for the directory entry. + +@item +On some systems, @code{readdir_r} cannot read directory entries with +very long names. If such a name is encountered, @theglibc{} +implementation of @code{readdir_r} returns with an error code of +@code{ENAMETOOLONG} after the final directory entry has been read. On +other systems, @code{readdir_r} may return successfully, but the +@code{d_name} member may not be NUL-terminated or may be truncated. + +@item +POSIX-1.2008 does not guarantee that @code{readdir} is thread-safe, +even when access to the same @var{dirstream} is serialized. But in +current implementations (including @theglibc{}), it is safe to call +@code{readdir} concurrently on different @var{dirstream}s, so there is +no need to use @code{readdir_r} in most multi-threaded programs. In +the rare case that multiple threads need to read from the same +@var{dirstream}, it is still better to use @code{readdir} and external +synchronization. + +@item +It is expected that future versions of POSIX will obsolete +@code{readdir_r} and mandate the level of thread safety for +@code{readdir} which is provided by @theglibc{} and other +implementations today. +@end itemize Normally @code{readdir_r} returns zero and sets @code{*@var{result}} to @var{entry}. If there are no more entries in the directory or an @@ -481,15 +523,6 @@ error is detected, @code{readdir_r} sets @code{*@var{result}} to a null pointer and returns a nonzero error code, also stored in @code{errno}, as described for @code{readdir}. -@strong{Portability Note:} On some systems @code{readdir_r} may not -return a NUL terminated string for the file name, even when there is no -@code{d_reclen} field in @code{struct dirent} and the file -name is the maximum allowed size. Modern systems all have the -@code{d_reclen} field, and on old systems multi-threading is not -critical. In any case there is no such problem with the @code{readdir} -function, so that even on systems without the @code{d_reclen} member one -could use multiple threads by using external locking. - It is also important to look at the definition of the @code{struct dirent} type. Simply passing a pointer to an object of this type for the second parameter of @code{readdir_r} might not be enough. Some diff --git a/sysdeps/posix/dirstream.h b/sysdeps/posix/dirstream.h index a7a074d..8e8570d 100644 --- a/sysdeps/posix/dirstream.h +++ b/sysdeps/posix/dirstream.h @@ -39,6 +39,8 @@ struct __dirstream off_t filepos; /* Position of next entry to read. */ + int errcode; /* Delayed error code. */ + /* Directory block. */ char data[0] __attribute__ ((aligned (__alignof__ (void*)))); }; diff --git a/sysdeps/posix/opendir.c b/sysdeps/posix/opendir.c index ddfc3a7..fc05b0f 100644 --- a/sysdeps/posix/opendir.c +++ b/sysdeps/posix/opendir.c @@ -231,6 +231,7 @@ __alloc_dir (int fd, bool close_fd, int flags, const struct stat64 *statp) dirp->size = 0; dirp->offset = 0; dirp->filepos = 0; + dirp->errcode = 0; return dirp; } diff --git a/sysdeps/posix/readdir_r.c b/sysdeps/posix/readdir_r.c index b5a8e2e..8ed5c3f 100644 --- a/sysdeps/posix/readdir_r.c +++ b/sysdeps/posix/readdir_r.c @@ -40,6 +40,7 @@ __READDIR_R (DIR *dirp, DIRENT_TYPE *entry, DIRENT_TYPE **result) DIRENT_TYPE *dp; size_t reclen; const int saved_errno = errno; + int ret; __libc_lock_lock (dirp->lock); @@ -70,10 +71,10 @@ __READDIR_R (DIR *dirp, DIRENT_TYPE *entry, DIRENT_TYPE **result) bytes = 0; __set_errno (saved_errno); } + if (bytes < 0) + dirp->errcode = errno; dp = NULL; - /* Reclen != 0 signals that an error occurred. */ - reclen = bytes != 0; break; } dirp->size = (size_t) bytes; @@ -106,29 +107,46 @@ __READDIR_R (DIR *dirp, DIRENT_TYPE *entry, DIRENT_TYPE **result) dirp->filepos += reclen; #endif - /* Skip deleted files. */ +#ifdef NAME_MAX + if (reclen > offsetof (DIRENT_TYPE, d_name) + NAME_MAX + 1) + { + /* The record is very long. It could still fit into the + caller-supplied buffer if we can skip padding at the + end. */ + size_t namelen = _D_EXACT_NAMLEN (dp); + if (namelen <= NAME_MAX) + reclen = offsetof (DIRENT_TYPE, d_name) + namelen + 1; + else + { + /* The name is too long. Ignore this file. */ + dirp->errcode = ENAMETOOLONG; + dp->d_ino = 0; + continue; + } + } +#endif + + /* Skip deleted and ignored files. */ } while (dp->d_ino == 0); if (dp != NULL) { -#ifdef GETDENTS_64BIT_ALIGNED - /* The d_reclen value might include padding which is not part of - the DIRENT_TYPE data structure. */ - reclen = MIN (reclen, - offsetof (DIRENT_TYPE, d_name) + sizeof (dp->d_name)); -#endif *result = memcpy (entry, dp, reclen); -#ifdef GETDENTS_64BIT_ALIGNED +#ifdef _DIRENT_HAVE_D_RECLEN entry->d_reclen = reclen; #endif + ret = 0; } else - *result = NULL; + { + *result = NULL; + ret = dirp->errcode; + } __libc_lock_unlock (dirp->lock); - return dp != NULL ? 0 : reclen ? errno : 0; + return ret; } #ifdef __READDIR_R_ALIAS diff --git a/sysdeps/posix/rewinddir.c b/sysdeps/posix/rewinddir.c index 2935a8e..d4991ad 100644 --- a/sysdeps/posix/rewinddir.c +++ b/sysdeps/posix/rewinddir.c @@ -33,6 +33,7 @@ rewinddir (dirp) dirp->filepos = 0; dirp->offset = 0; dirp->size = 0; + dirp->errcode = 0; #ifndef NOT_IN_libc __libc_lock_unlock (dirp->lock); #endif diff --git a/sysdeps/unix/sysv/linux/i386/readdir64_r.c b/sysdeps/unix/sysv/linux/i386/readdir64_r.c index 8ebbcfd..a7d114e 100644 --- a/sysdeps/unix/sysv/linux/i386/readdir64_r.c +++ b/sysdeps/unix/sysv/linux/i386/readdir64_r.c @@ -18,7 +18,6 @@ #define __READDIR_R __readdir64_r #define __GETDENTS __getdents64 #define DIRENT_TYPE struct dirent64 -#define GETDENTS_64BIT_ALIGNED 1 #include <sysdeps/posix/readdir_r.c> diff --git a/sysdeps/unix/sysv/linux/wordsize-64/readdir_r.c b/sysdeps/unix/sysv/linux/wordsize-64/readdir_r.c index 5ed8e95..290f2c8 100644 --- a/sysdeps/unix/sysv/linux/wordsize-64/readdir_r.c +++ b/sysdeps/unix/sysv/linux/wordsize-64/readdir_r.c @@ -1,5 +1,4 @@ #define readdir64_r __no_readdir64_r_decl -#define GETDENTS_64BIT_ALIGNED 1 #include <sysdeps/posix/readdir_r.c> #undef readdir64_r weak_alias (__readdir_r, readdir64_r) |