From: Florian Weimer <fweimer@redhat.com>
To: libc-alpha@sourceware.org
Subject: [PATCH v3 07/32] elf: Disambiguate some failures in _dl_load_cache_lookup
Date: Thu, 07 Dec 2023 11:31:33 +0100 [thread overview]
Message-ID: <37bdcf0c7d559672bb913bb55cf681d60a6c30d8.1701944612.git.fweimer@redhat.com> (raw)
In-Reply-To: <cover.1701944612.git.fweimer@redhat.com>
Failure to allocate a copy of the string is now distinct from
a cache lookup failure. Some infrastructure failures in
_dl_sysdep_read_whole_file are still treated as cache lookup
failures, though.
---
elf/dl-cache.c | 22 ++++++++++++++++------
elf/dl-load.c | 5 ++++-
sysdeps/generic/ldsodefs.h | 10 +++++++---
3 files changed, 27 insertions(+), 10 deletions(-)
diff --git a/elf/dl-cache.c b/elf/dl-cache.c
index 804bf23222..a3eb960dac 100644
--- a/elf/dl-cache.c
+++ b/elf/dl-cache.c
@@ -398,8 +398,8 @@ _dl_cache_libcmp (const char *p1, const char *p2)
may be unmapped at any time by a completing recursive dlopen and
this function must take care that it does not return references to
any data in the mapping. */
-char *
-_dl_load_cache_lookup (const char *name)
+bool
+_dl_load_cache_lookup (const char *name, char **realname)
{
/* Print a message if the loading of libs is traced. */
if (__glibc_unlikely (GLRO(dl_debug_mask) & DL_DEBUG_LIBS))
@@ -475,8 +475,11 @@ _dl_load_cache_lookup (const char *name)
}
if (cache == (void *) -1)
- /* Previously looked for the cache file and didn't find it. */
- return NULL;
+ {
+ /* Previously looked for the cache file and didn't find it. */
+ *realname = NULL;
+ return true;
+ }
const char *best;
if (cache_new != (void *) -1)
@@ -502,7 +505,10 @@ _dl_load_cache_lookup (const char *name)
_dl_debug_printf (" trying file=%s\n", best);
if (best == NULL)
- return NULL;
+ {
+ *realname = NULL;
+ return true;
+ }
/* The double copy is *required* since malloc may be interposed
and call dlopen itself whose completion would unmap the data
@@ -512,7 +518,11 @@ _dl_load_cache_lookup (const char *name)
size_t best_len = strlen (best) + 1;
temp = alloca (best_len);
memcpy (temp, best, best_len);
- return __strdup (temp);
+ char *copy = __strdup (temp);
+ if (copy == NULL)
+ return false;
+ *realname = copy;
+ return true;
}
#ifndef MAP_COPY
diff --git a/elf/dl-load.c b/elf/dl-load.c
index 65f910f0e5..2084366663 100644
--- a/elf/dl-load.c
+++ b/elf/dl-load.c
@@ -2082,7 +2082,10 @@ _dl_map_object (struct link_map *loader, const char *name,
{
/* Check the list of libraries in the file /etc/ld.so.cache,
for compatibility with Linux's ldconfig program. */
- char *cached = _dl_load_cache_lookup (name);
+ char *cached;
+ if (!_dl_load_cache_lookup (name, &cached))
+ _dl_signal_error (ENOMEM, NULL, NULL,
+ N_("cannot allocate library name"));
if (cached != NULL)
{
diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h
index 9b50ddd09f..80f078b65f 100644
--- a/sysdeps/generic/ldsodefs.h
+++ b/sysdeps/generic/ldsodefs.h
@@ -1111,9 +1111,13 @@ const struct r_strlenpair *_dl_important_hwcaps (const char *prepend,
size_t *max_capstrlen)
attribute_hidden;
-/* Look up NAME in ld.so.cache and return the file name stored there,
- or null if none is found. Caller must free returned string. */
-extern char *_dl_load_cache_lookup (const char *name) attribute_hidden;
+/* Look up NAME in ld.so.cache. Return false on memory allocation
+ failure and do not change *REALNAME. If lookup fails, return true
+ and write a null pointer to *REALNAME. If lookup suceeds, write a
+ copy of the full name to *REALNAME (which has to be freed by the
+ caller). */
+bool _dl_load_cache_lookup (const char *name, char **realname)
+ attribute_hidden __nonnull ((1, 2)) __attribute__ ((warn_unused_result));
/* If the system does not support MAP_COPY we cannot leave the file open
all the time since this would create problems when the file is replaced.
--
2.43.0
next prev parent reply other threads:[~2023-12-07 10:31 UTC|newest]
Thread overview: 77+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-07 10:30 [PATCH v3 00/32] RELRO linkmaps Florian Weimer
2023-12-07 10:30 ` [PATCH v3 01/32] support: Add <support/memprobe.h> for protection flags probing Florian Weimer
2024-02-22 22:39 ` Joseph Myers
2023-12-07 10:30 ` [PATCH v3 02/32] misc: Enable internal use of memory protection keys Florian Weimer
2024-02-22 1:06 ` Joseph Myers
2023-12-07 10:31 ` [PATCH v3 03/32] elf: Remove _dl_sysdep_open_object hook function Florian Weimer
2024-01-31 13:10 ` Joseph Myers
2024-03-11 17:19 ` Florian Weimer
2024-03-11 17:33 ` Joseph Myers
2024-03-11 17:46 ` Florian Weimer
2024-03-11 18:02 ` Joseph Myers
2024-03-11 18:16 ` Florian Weimer
2023-12-07 10:31 ` [PATCH v3 04/32] elf: Eliminate second loop in find_version in dl-version.c Florian Weimer
2024-02-19 22:17 ` Joseph Myers
2023-12-07 10:31 ` [PATCH v3 05/32] elf: In rtld_setup_main_map, assume ld.so has a DYNAMIC segment Florian Weimer
2024-02-19 22:18 ` Joseph Myers
2023-12-07 10:31 ` [PATCH v3 06/32] elf: Remove version assert in check_match in elf/dl-lookup.c Florian Weimer
2024-03-04 23:22 ` Joseph Myers
2023-12-07 10:31 ` Florian Weimer [this message]
2024-02-19 23:07 ` [PATCH v3 07/32] elf: Disambiguate some failures in _dl_load_cache_lookup Joseph Myers
2023-12-07 10:31 ` [PATCH v3 08/32] elf: Eliminate alloca in open_verify Florian Weimer
2024-02-19 23:26 ` Joseph Myers
2023-12-07 10:31 ` [PATCH v3 09/32] Do not export <alloc_buffer.h> functions from libc Florian Weimer
2024-02-21 17:13 ` Joseph Myers
2023-12-07 10:31 ` [PATCH v3 10/32] elf: Make <alloc_buffer.h> usable in ld.so Florian Weimer
2024-02-21 17:19 ` Joseph Myers
2023-12-07 10:31 ` [PATCH v3 11/32] elf: Merge the three implementations of _dl_dst_substitute Florian Weimer
2024-02-28 17:52 ` Joseph Myers
2023-12-07 10:31 ` [PATCH v3 12/32] elf: Move __rtld_malloc_init_stubs call into _dl_start_final Florian Weimer
2024-02-22 22:30 ` Joseph Myers
2024-02-22 23:06 ` Andreas Schwab
2023-12-07 10:31 ` [PATCH v3 13/32] elf: Merge __dl_libc_freemem into __rtld_libc_freeres Florian Weimer
2024-02-22 23:23 ` Joseph Myers
2023-12-07 10:31 ` [PATCH v3 14/32] elf: Use struct link_map_private for the internal link map Florian Weimer
2024-02-22 23:36 ` Joseph Myers
2023-12-07 10:32 ` [PATCH v3 15/32] elf: Remove run-time-writable fields from struct link_map_private Florian Weimer
2024-02-23 0:09 ` Joseph Myers
2023-12-07 10:32 ` [PATCH v3 16/32] elf: Move l_tls_offset into read-write part of link map Florian Weimer
2024-02-26 21:57 ` Joseph Myers
2023-12-07 10:32 ` [PATCH v3 17/32] elf: Allocate auditor state after read-write " Florian Weimer
2024-02-26 22:01 ` Joseph Myers
2023-12-07 10:32 ` [PATCH v3 18/32] elf: Move link map fields used by dependency sorting to writable part Florian Weimer
2024-02-27 17:51 ` Joseph Myers
2023-12-07 10:32 ` [PATCH v3 19/32] elf: Split _dl_lookup_map, _dl_map_new_object from _dl_map_object Florian Weimer
2024-02-27 17:56 ` Joseph Myers
2023-12-07 10:32 ` [PATCH v3 20/32] elf: Add l_soname accessor function for DT_SONAME values Florian Weimer
2024-02-27 22:14 ` Joseph Myers
2023-12-07 10:32 ` [PATCH v3 21/32] elf: _dl_rtld_map should not exist in static builds Florian Weimer
2024-02-28 12:38 ` Joseph Myers
2023-12-07 10:32 ` [PATCH v3 22/32] elf: Introduce GLPM accessor for the protected memory area Florian Weimer
2024-02-28 12:44 ` Joseph Myers
2023-12-07 10:32 ` [PATCH v3 23/32] elf: Bootstrap allocation for future protected memory allocator Florian Weimer
2024-02-28 15:04 ` Joseph Myers
2023-12-07 10:32 ` [PATCH v3 24/32] elf: Implement a basic " Florian Weimer
2024-02-28 18:46 ` Joseph Myers
2023-12-07 10:32 ` [PATCH v3 25/32] elf: Move most of the _dl_find_object data to the protected heap Florian Weimer
2024-02-28 19:06 ` Joseph Myers
2023-12-07 10:32 ` [PATCH v3 26/32] elf: Switch to a region-based protected memory allocator Florian Weimer
2024-03-05 23:36 ` Joseph Myers
2023-12-07 10:32 ` [PATCH v3 27/32] elf: Determine the caller link map in _dl_open Florian Weimer
2024-02-28 19:23 ` Joseph Myers
2023-12-07 10:32 ` [PATCH v3 28/32] elf: Add fast path to dlopen for fully-opened maps Florian Weimer
2024-02-28 19:26 ` Joseph Myers
2023-12-07 10:32 ` [PATCH v3 29/32] elf: Use _dl_find_object instead of _dl_find_dso_for_object in dlopen Florian Weimer
2024-02-28 19:27 ` Joseph Myers
2023-12-07 10:32 ` [PATCH v3 30/32] elf: Put critical _dl_find_object pointers into protected memory area Florian Weimer
2024-03-04 21:39 ` Joseph Myers
2023-12-07 10:32 ` [PATCH v3 31/32] elf: Add hash tables to speed up DT_NEEDED, dlopen lookups Florian Weimer
2024-03-06 0:04 ` Joseph Myers
2023-12-07 10:33 ` [PATCH v3 32/32] elf: Use memory protection keys for the protected memory allocator Florian Weimer
2024-03-06 0:11 ` Joseph Myers
2023-12-07 10:53 ` [PATCH v3 00/32] RELRO linkmaps Andreas Schwab
2023-12-07 10:56 ` Florian Weimer
2023-12-07 11:34 ` Andreas Schwab
2024-03-01 14:45 ` Adhemerval Zanella Netto
2024-03-11 17:24 ` Florian Weimer
2024-03-12 12:51 ` Adhemerval Zanella Netto
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=37bdcf0c7d559672bb913bb55cf681d60a6c30d8.1701944612.git.fweimer@redhat.com \
--to=fweimer@redhat.com \
--cc=libc-alpha@sourceware.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).