From 8e889c5da3c5981c5a46a93fec02de40131ac5a6 Mon Sep 17 00:00:00 2001 From: Adhemerval Zanella Date: Wed, 23 Jan 2019 11:42:54 -0200 Subject: elf: Fix LD_AUDIT for modules with invalid version (BZ#24122) The error handling patch for invalid audit modules version access invalid memory: elf/rtld.c: 1454 unsigned int (*laversion) (unsigned int); 1455 unsigned int lav; 1456 if (err_str == NULL 1457 && (laversion = largs.result) != NULL 1458 && (lav = laversion (LAV_CURRENT)) > 0 1459 && lav <= LAV_CURRENT) 1460 { [...] 1526 else 1527 { 1528 /* We cannot use the DSO, it does not have the 1529 appropriate interfaces or it expects something 1530 more recent. */ 1531 #ifndef NDEBUG 1532 Lmid_t ns = dlmargs.map->l_ns; 1533 #endif 1534 _dl_close (dlmargs.map); 1535 1536 /* Make sure the namespace has been cleared entirely. */ 1537 assert (GL(dl_ns)[ns]._ns_loaded == NULL); 1538 assert (GL(dl_ns)[ns]._ns_nloaded == 0); 1539 1540 GL(dl_tls_max_dtv_idx) = tls_idx; 1541 goto not_loaded; 1542 } 1431 const char *err_str = NULL; 1432 bool malloced; 1433 (void) _dl_catch_error (&objname, &err_str, &malloced, dlmopen_doit, 1434 &dlmargs); 1435 if (__glibc_unlikely (err_str != NULL)) 1436 { 1437 not_loaded: 1438 _dl_error_printf ("\ 1439 ERROR: ld.so: object '%s' cannot be loaded as audit interface: %s; ignored.\n", 1440 name, err_str); 1441 if (malloced) 1442 free ((char *) err_str); 1443 } On failure the err_str will be NULL and _dl_debug_vdprintf does not handle it properly: elf/dl-misc.c: 200 case 's': 201 /* Get the string argument. */ 202 iov[niov].iov_base = va_arg (arg, char *); 203 iov[niov].iov_len = strlen (iov[niov].iov_base); 204 if (prec != -1) 205 iov[niov].iov_len = MIN ((size_t) prec, iov[niov].iov_len); 206 ++niov; 207 break; This patch fixes the issues and improves the error message. Checked on x86_64-linux-gnu and i686-linux-gnu [BZ #24122] * elf/Makefile (tests): Add tst-audit13. (modules-names): Add tst-audit13mod1. (tst-audit13.out, LDFLAGS-tst-audit13mod1.so, tst-audit13-ENV): New rule. * elf/rtld.c (dl_main): Handle invalid audit module version. * elf/tst-audit13.c: New file. * elf/tst-audit13mod1.c: Likewise. Reviewed-by: Carlos O'Donell --- elf/rtld.c | 30 +++++++++++++++++++++++++----- 1 file changed, 25 insertions(+), 5 deletions(-) (limited to 'elf/rtld.c') diff --git a/elf/rtld.c b/elf/rtld.c index 5d97f41..9e0f752 100644 --- a/elf/rtld.c +++ b/elf/rtld.c @@ -1453,10 +1453,12 @@ ERROR: ld.so: object '%s' cannot be loaded as audit interface: %s; ignored.\n", unsigned int (*laversion) (unsigned int); unsigned int lav; - if (err_str == NULL - && (laversion = largs.result) != NULL - && (lav = laversion (LAV_CURRENT)) > 0 - && lav <= LAV_CURRENT) + if (err_str != NULL) + goto not_loaded; + + if ((laversion = largs.result) != NULL + && (lav = laversion (LAV_CURRENT)) > 0 + && lav <= LAV_CURRENT) { /* Allocate structure for the callback function pointers. This call can never fail. */ @@ -1538,7 +1540,25 @@ ERROR: ld.so: object '%s' cannot be loaded as audit interface: %s; ignored.\n", assert (GL(dl_ns)[ns]._ns_nloaded == 0); GL(dl_tls_max_dtv_idx) = tls_idx; - goto not_loaded; + if (GLRO(dl_debug_mask) & DL_DEBUG_FILES) + { + _dl_debug_printf ("\ +\nfile=%s cannot be loaded as audit interface; ignored.\n", name); + if (laversion == NULL) + _dl_debug_printf ( +" la_version function not found.\n"); + else + { + if (lav == 0) + _dl_debug_printf ( +" auditor requested to be ignored (returned version of 0).\n"); + else + _dl_debug_printf ( +" auditor disabled since expected version %d is greater than " +"supported version %d.\n", + lav, LAV_CURRENT); + } + } } } } -- cgit v1.1