From f64a75b648e854e669fa75843e8627d8ed842b54 Mon Sep 17 00:00:00 2001 From: Siddhesh Poyarekar Date: Aug 19 2013 08:03:34 +0000 Subject: Fix buffer overflow in readdir_r (#995841, CVE-2013-4237) --- diff --git a/glibc-rh995841.patch b/glibc-rh995841.patch new file mode 100644 index 0000000..f745cb0 --- /dev/null +++ b/glibc-rh995841.patch @@ -0,0 +1,302 @@ +commit 91ce40854d0b7f865cf5024ef95a8026b76096f3 +Author: Florian Weimer +Date: Fri Aug 16 09:38:52 2013 +0200 + + CVE-2013-4237, BZ #14699: Buffer overflow in readdir_r + + * 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. + +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 + +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 + #undef readdir64_r + weak_alias (__readdir_r, readdir64_r) diff --git a/glibc.spec b/glibc.spec index ac1dfeb..acd73e6 100644 --- a/glibc.spec +++ b/glibc.spec @@ -1,6 +1,6 @@ %define glibcsrcdir glibc-2.18 %define glibcversion 2.18 -%define glibcrelease 1%{?dist} +%define glibcrelease 2%{?dist} # Pre-release tarballs are pulled in from git using a command that is # effectively: # @@ -171,6 +171,7 @@ Patch0037: %{name}-rh952799.patch # # Patches from upstream # +Patch1001: %{name}-rh995841.patch # # Patches submitted, but not yet approved upstream. @@ -514,6 +515,7 @@ package or when debugging this package. %patch0035 -p1 %patch0037 -p1 %patch2028 -p1 +%patch1001 -p1 ############################################################################## # %%prep - Additional prep required... @@ -1594,6 +1596,9 @@ rm -f *.filelist* %endif %changelog +* Mon Aug 19 2013 Siddhesh Poyarekar - 2.18-2 +- Fix buffer overflow in readdir_r (#995841, CVE-2013-4237). + * Fri Aug 16 2013 Siddhesh Poyarekar - 2.18-1 - Upstream release 2.18. - Pull in systemd during build and use the tmpfilesdir macro.