diff options
Diffstat (limited to 'misc')
| -rw-r--r-- | misc/Makefile | 8 | ||||
| -rw-r--r-- | misc/syslog.c | 50 | ||||
| -rw-r--r-- | misc/tst-syslog-long-progname.c | 39 | ||||
| -rw-r--r-- | misc/tst-syslog-long-progname.root/postclean.req | 0 |
4 files changed, 82 insertions, 15 deletions
diff --git a/misc/Makefile b/misc/Makefile index 42899c2b6c..c273ec6974 100644 --- a/misc/Makefile +++ b/misc/Makefile @@ -289,7 +289,10 @@ tests-special += $(objpfx)tst-error1-mem.out \ $(objpfx)tst-allocate_once-mem.out endif -tests-container := tst-syslog +tests-container := \ + tst-syslog \ + tst-syslog-long-progname \ + # tests-container CFLAGS-select.c += -fexceptions -fasynchronous-unwind-tables CFLAGS-tsearch.c += $(uses-callbacks) @@ -351,6 +354,9 @@ $(objpfx)tst-allocate_once-mem.out: $(objpfx)tst-allocate_once.out $(common-objpfx)malloc/mtrace $(objpfx)tst-allocate_once.mtrace > $@; \ $(evaluate-test) +tst-syslog-long-progname-ENV = GLIBC_TUNABLES=glibc.malloc.check=3 \ + LD_PRELOAD=libc_malloc_debug.so.0 + $(objpfx)tst-select: $(librt) $(objpfx)tst-select-time64: $(librt) $(objpfx)tst-pselect: $(librt) diff --git a/misc/syslog.c b/misc/syslog.c index 1b8cb722c5..814d224a1e 100644 --- a/misc/syslog.c +++ b/misc/syslog.c @@ -124,8 +124,9 @@ __vsyslog_internal (int pri, const char *fmt, va_list ap, { /* Try to use a static buffer as an optimization. */ char bufs[1024]; - char *buf = NULL; - size_t bufsize = 0; + char *buf = bufs; + size_t bufsize; + int msgoff; int saved_errno = errno; @@ -177,29 +178,50 @@ __vsyslog_internal (int pri, const char *fmt, va_list ap, #define SYSLOG_HEADER_WITHOUT_TS(__pri, __msgoff) \ "<%d>: %n", __pri, __msgoff - int l; + int l, vl; if (has_ts) l = __snprintf (bufs, sizeof bufs, SYSLOG_HEADER (pri, timestamp, &msgoff, pid)); else l = __snprintf (bufs, sizeof bufs, SYSLOG_HEADER_WITHOUT_TS (pri, &msgoff)); + + char *pos; + size_t len; + if (0 <= l && l < sizeof bufs) { - va_list apc; - va_copy (apc, ap); + /* At this point, there is still a chance that we can print the + remaining part of the log into bufs and use that. */ + pos = bufs + l; + len = sizeof (bufs) - l; + } + else + { + buf = NULL; + /* We already know that bufs is too small to use for this log message. + The next vsnprintf into bufs is used only to calculate the total + required buffer length. We will discard bufs contents and allocate + an appropriately sized buffer later instead. */ + pos = bufs; + len = sizeof (bufs); + } - /* Restore errno for %m format. */ - __set_errno (saved_errno); + { + va_list apc; + va_copy (apc, ap); - int vl = __vsnprintf_internal (bufs + l, sizeof bufs - l, fmt, apc, - mode_flags); - if (0 <= vl && vl < sizeof bufs - l) - buf = bufs; - bufsize = l + vl; + /* Restore errno for %m format. */ + __set_errno (saved_errno); - va_end (apc); - } + vl = __vsnprintf_internal (pos, len, fmt, apc, mode_flags); + + if (!(0 <= vl && vl < len)) + buf = NULL; + + bufsize = l + vl; + va_end (apc); + } if (buf == NULL) { diff --git a/misc/tst-syslog-long-progname.c b/misc/tst-syslog-long-progname.c new file mode 100644 index 0000000000..88f37a8a00 --- /dev/null +++ b/misc/tst-syslog-long-progname.c @@ -0,0 +1,39 @@ +/* Test heap buffer overflow in syslog with long __progname (CVE-2023-6246) + Copyright (C) 2023 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <https://www.gnu.org/licenses/>. */ + +#include <syslog.h> +#include <string.h> + +extern char * __progname; + +static int +do_test (void) +{ + char long_progname[2048]; + + memset (long_progname, 'X', sizeof (long_progname) - 1); + long_progname[sizeof (long_progname) - 1] = '\0'; + + __progname = long_progname; + + syslog (LOG_INFO, "Hello, World!"); + + return 0; +} + +#include <support/test-driver.c> diff --git a/misc/tst-syslog-long-progname.root/postclean.req b/misc/tst-syslog-long-progname.root/postclean.req new file mode 100644 index 0000000000..e69de29bb2 --- /dev/null +++ b/misc/tst-syslog-long-progname.root/postclean.req |