From: Szabolcs Nagy <szabolcs.nagy@arm.com>
To: libc-alpha@sourceware.org
Cc: Mark Rutland <mark.rutland@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
linux-kernel@vger.kernel.org,
Jeremy Linton <jeremy.linton@arm.com>,
Mark Brown <broonie@kernel.org>,
kernel-hardening@lists.openwall.com,
Topi Miettinen <toiwoton@gmail.com>,
linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 3/6] elf: Fix failure handling in _dl_map_object_from_fd
Date: Fri, 27 Nov 2020 13:20:29 +0000 [thread overview]
Message-ID: <8ebf571196dd499c61983dbf53c94c68ebd458cc.1606319495.git.szabolcs.nagy@arm.com> (raw)
In-Reply-To: <cover.1606319495.git.szabolcs.nagy@arm.com>
There are many failure paths that call lose to do local cleanups
in _dl_map_object_from_fd, but it did not clean everything.
Handle l_phdr, l_libname and mapped segments in the common failure
handling code.
There are various bits that may not be cleaned properly on failure
(e.g. executable stack, tlsid, incomplete dl_map_segments).
---
elf/dl-load.c | 24 +++++++++++++++---------
1 file changed, 15 insertions(+), 9 deletions(-)
diff --git a/elf/dl-load.c b/elf/dl-load.c
index 21e55deb19..9c71b7562c 100644
--- a/elf/dl-load.c
+++ b/elf/dl-load.c
@@ -914,8 +914,15 @@ lose (int code, int fd, const char *name, char *realname, struct link_map *l,
/* The file might already be closed. */
if (fd != -1)
(void) __close_nocancel (fd);
+ if (l != NULL && l->l_map_start != 0)
+ _dl_unmap_segments (l);
if (l != NULL && l->l_origin != (char *) -1l)
free ((char *) l->l_origin);
+ if (l != NULL && !l->l_libname->dont_free)
+ free (l->l_libname);
+ if (l != NULL && l->l_phdr_allocated)
+ free ((void *) l->l_phdr);
+
free (l);
free (realname);
@@ -1256,7 +1263,11 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
errstring = _dl_map_segments (l, fd, header, type, loadcmds, nloadcmds,
maplength, has_holes, loader);
if (__glibc_unlikely (errstring != NULL))
- goto call_lose;
+ {
+ /* Mappings can be in an inconsistent state: avoid unmap. */
+ l->l_map_start = l->l_map_end = 0;
+ goto call_lose;
+ }
/* Process program headers again after load segments are mapped in
case processing requires accessing those segments. Scan program
@@ -1294,14 +1305,6 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
|| (__glibc_unlikely (l->l_flags_1 & DF_1_PIE)
&& __glibc_unlikely ((mode & __RTLD_OPENEXEC) == 0)))
{
- /* We are not supposed to load this object. Free all resources. */
- _dl_unmap_segments (l);
-
- if (!l->l_libname->dont_free)
- free (l->l_libname);
-
- if (l->l_phdr_allocated)
- free ((void *) l->l_phdr);
if (l->l_flags_1 & DF_1_PIE)
errstring
@@ -1392,6 +1395,9 @@ cannot enable executable stack as shared object requires");
/* Signal that we closed the file. */
fd = -1;
+ /* Failures before this point are handled locally via lose.
+ No more failures are allowed in this function until return. */
+
/* If this is ET_EXEC, we should have loaded it as lt_executable. */
assert (type != ET_EXEC || l->l_type == lt_executable);
--
2.17.1
next prev parent reply other threads:[~2020-11-27 13:20 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-27 13:19 [PATCH v2 0/6] aarch64: avoid mprotect(PROT_BTI|PROT_EXEC) [BZ #26831] Szabolcs Nagy
2020-11-27 13:19 ` [PATCH v2 1/6] aarch64: Fix missing BTI protection from dependencies [BZ #26926] Szabolcs Nagy
2020-12-10 17:51 ` Adhemerval Zanella
2020-12-11 15:33 ` Szabolcs Nagy
2020-11-27 13:20 ` [PATCH v2 2/6] elf: lose is closely tied to _dl_map_object_from_fd Szabolcs Nagy
2020-12-10 17:57 ` Adhemerval Zanella
2020-12-11 12:12 ` Szabolcs Nagy
2020-11-27 13:20 ` Szabolcs Nagy [this message]
2020-12-10 18:25 ` [PATCH v2 3/6] elf: Fix failure handling in _dl_map_object_from_fd Adhemerval Zanella
2020-12-11 9:32 ` Szabolcs Nagy
2020-11-27 13:20 ` [PATCH v2 4/6] elf: Move note processing after l_phdr is updated Szabolcs Nagy
2020-12-10 18:30 ` Adhemerval Zanella
2020-11-27 13:21 ` [PATCH v2 5/6] elf: Pass the fd to note processing Szabolcs Nagy
2020-12-10 18:35 ` Adhemerval Zanella
2020-11-27 13:21 ` [PATCH v2 6/6] aarch64: Use mmap to add PROT_BTI instead of mprotect [BZ #26831] Szabolcs Nagy
2020-12-02 8:55 ` [PATCH v3 1/2] aarch64: align address for BTI protection [BZ #26988] Szabolcs Nagy
2020-12-10 18:49 ` Adhemerval Zanella
2020-12-02 8:55 ` [PATCH v3 2/2] aarch64: Use mmap to add PROT_BTI instead of mprotect [BZ #26831] Szabolcs Nagy
2020-12-10 19:12 ` Adhemerval Zanella
2020-11-30 15:56 ` [PATCH v2 0/6] aarch64: avoid mprotect(PROT_BTI|PROT_EXEC) " Szabolcs Nagy
2020-12-03 17:30 ` Catalin Marinas
2020-12-07 20:03 ` Szabolcs Nagy
2020-12-11 17:46 ` Catalin Marinas
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