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| author | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2025-03-14 16:09:57 -0300 |
|---|---|---|
| committer | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2025-03-21 15:46:48 -0300 |
| commit | ed6a68bac7cd056abda9008019c71b167f0362dc (patch) | |
| tree | 7ceb7f6403f423e4773724c518e537e13f140a3d /stdio-common/vfprintf-internal.c | |
| parent | 1894e219dc530d7074085e95ffe3c1e66cebc072 (diff) | |
| download | glibc-ed6a68bac7cd056abda9008019c71b167f0362dc.tar.xz glibc-ed6a68bac7cd056abda9008019c71b167f0362dc.zip | |
debug: Improve '%n' fortify detection (BZ 30932)
The 7bb8045ec0 path made the '%n' fortify check ignore EMFILE errors
while trying to open /proc/self/maps, and this added a security
issue where EMFILE can be attacker-controlled thus making it
ineffective for some cases.
The EMFILE failure is reinstated but with a different error
message. Also, to improve the false positive of the hardening for
the cases where no new files can be opened, the
_dl_readonly_area now uses _dl_find_object to check if the
memory area is within a writable ELF segment. The procfs method is
still used as fallback.
Checked on x86_64-linux-gnu and i686-linux-gnu.
Reviewed-by: Arjun Shankar <arjun@redhat.com>
Diffstat (limited to 'stdio-common/vfprintf-internal.c')
| -rw-r--r-- | stdio-common/vfprintf-internal.c | 9 |
1 files changed, 4 insertions, 5 deletions
diff --git a/stdio-common/vfprintf-internal.c b/stdio-common/vfprintf-internal.c index aa9708bff5..fa41e1b242 100644 --- a/stdio-common/vfprintf-internal.c +++ b/stdio-common/vfprintf-internal.c @@ -576,7 +576,8 @@ static const uint8_t jump_table[] = /* Handle positional format specifiers. */ static void printf_positional (struct Xprintf_buffer *buf, - const CHAR_T *format, int readonly_format, + const CHAR_T *format, + enum readonly_error_type readonly_format, va_list ap, va_list *ap_savep, int nspecs_done, const UCHAR_T *lead_str_end, CHAR_T *work_buffer, int save_errno, @@ -626,9 +627,7 @@ Xprintf_buffer (struct Xprintf_buffer *buf, const CHAR_T *format, /* For the %m format we may need the current `errno' value. */ int save_errno = errno; - /* 1 if format is in read-only memory, -1 if it is in writable memory, - 0 if unknown. */ - int readonly_format = 0; + enum readonly_error_type readonly_format = readonly_noerror; /* Initialize local variables. */ grouping = (const char *) -1; @@ -1045,7 +1044,7 @@ do_positional: static void printf_positional (struct Xprintf_buffer * buf, const CHAR_T *format, - int readonly_format, + enum readonly_error_type readonly_format, va_list ap, va_list *ap_savep, int nspecs_done, const UCHAR_T *lead_str_end, CHAR_T *work_buffer, int save_errno, |