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author | Florian Weimer <fweimer@redhat.com> | 2019-08-19 15:41:29 +0200 |
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committer | Florian Weimer <fweimer@redhat.com> | 2019-08-19 15:41:29 +0200 |
commit | a289ea09ea843ced6e5277c2f2e63c357bc7f9a3 (patch) | |
tree | 0b8a004ed5794f6f6bff89dbdc44518cb41bb373 /sysdeps/unix/sysv/linux | |
parent | 1d714fd95da16f0d97c8c670a2c899f99c01eb45 (diff) | |
download | glibc-a289ea09ea843ced6e5277c2f2e63c357bc7f9a3.tar.gz glibc-a289ea09ea843ced6e5277c2f2e63c357bc7f9a3.tar.xz glibc-a289ea09ea843ced6e5277c2f2e63c357bc7f9a3.zip |
Do not print backtraces on fatal glibc errors
If the process is in a bad state, we used to print backtraces in many cases. This is problematic because doing so could involve a lot of work, like loading libgcc_s using the dynamic linker, and this could itself be targeted by exploit writers. For example, if the crashing process was forked from a long-lived process, the addresses in the error message could be used to bypass ASLR. Commit ed421fca42fd9b4cab7c66e77894b8dd7ca57ed0 ("Avoid backtrace from __stack_chk_fail [BZ #12189]"), backtraces where no longer printed because backtrace_and_maps was always called with do_abort == 1. Rather than fixing this logic error, this change removes the backtrace functionality from the sources. With the prevalence of external crash handlers, it does not appear to be particularly useful. The crash handler may also destroy useful information for debugging. Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Diffstat (limited to 'sysdeps/unix/sysv/linux')
-rw-r--r-- | sysdeps/unix/sysv/linux/libc_fatal.c | 33 |
1 files changed, 0 insertions, 33 deletions
diff --git a/sysdeps/unix/sysv/linux/libc_fatal.c b/sysdeps/unix/sysv/linux/libc_fatal.c index 56c626339f..50a613e31f 100644 --- a/sysdeps/unix/sysv/linux/libc_fatal.c +++ b/sysdeps/unix/sysv/linux/libc_fatal.c @@ -17,11 +17,6 @@ <http://www.gnu.org/licenses/>. */ #include <errno.h> -#include <execinfo.h> -#include <fcntl.h> -#include <not-cancel.h> -#include <string.h> -#include <sys/mman.h> #include <sys/uio.h> static bool @@ -37,32 +32,4 @@ writev_for_fatal (int fd, const struct iovec *iov, size_t niov, size_t total) } #define WRITEV_FOR_FATAL writev_for_fatal -static void -backtrace_and_maps (int do_abort, bool written, int fd) -{ - if (do_abort > 1 && written) - { - void *addrs[64]; -#define naddrs (sizeof (addrs) / sizeof (addrs[0])) - int n = __backtrace (addrs, naddrs); - if (n > 2) - { -#define strnsize(str) str, strlen (str) -#define writestr(str) __write_nocancel (fd, str) - writestr (strnsize ("======= Backtrace: =========\n")); - __backtrace_symbols_fd (addrs + 1, n - 1, fd); - - writestr (strnsize ("======= Memory map: ========\n")); - int fd2 = __open_nocancel ("/proc/self/maps", O_RDONLY); - char buf[1024]; - ssize_t n2; - while ((n2 = __read_nocancel (fd2, buf, sizeof (buf))) > 0) - if (__write_nocancel (fd, buf, n2) != n2) - break; - __close_nocancel_nostatus (fd2); - } - } -} -#define BEFORE_ABORT backtrace_and_maps - #include <sysdeps/posix/libc_fatal.c> |