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
WARNING: multiple messages have this Message-ID (diff)
From: Szabolcs Nagy <szabolcs.nagy@arm.com> To: libc-alpha@sourceware.org Cc: Mark Rutland <mark.rutland@arm.com>, kernel-hardening@lists.openwall.com, Catalin Marinas <catalin.marinas@arm.com>, linux-kernel@vger.kernel.org, Jeremy Linton <jeremy.linton@arm.com>, Mark Brown <broonie@kernel.org>, Topi Miettinen <toiwoton@gmail.com>, Will Deacon <will@kernel.org>, 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 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-11-27 13:21 UTC|newest] Thread overview: 40+ 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 ` Szabolcs Nagy 2020-11-27 13:19 ` [PATCH v2 1/6] aarch64: Fix missing BTI protection from dependencies [BZ #26926] Szabolcs Nagy 2020-11-27 13:19 ` Szabolcs Nagy 2020-12-10 17:51 ` Adhemerval Zanella 2020-12-10 17:51 ` Adhemerval Zanella 2020-12-11 15:33 ` Szabolcs Nagy 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 2020-11-27 13:20 ` Szabolcs Nagy 2020-11-27 13:20 ` Szabolcs Nagy [this message] 2020-11-27 13:20 ` [PATCH v2 3/6] elf: Fix failure handling in _dl_map_object_from_fd Szabolcs Nagy 2020-12-10 18:25 ` Adhemerval Zanella 2020-12-10 18:25 ` Adhemerval Zanella 2020-12-11 9:32 ` Szabolcs Nagy 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 2020-11-27 13:20 ` Szabolcs Nagy 2020-11-27 13:21 ` [PATCH v2 5/6] elf: Pass the fd to note processing Szabolcs Nagy 2020-11-27 13:21 ` Szabolcs Nagy 2020-12-10 18:35 ` Adhemerval Zanella 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 2020-11-27 13:21 ` Szabolcs Nagy 2020-12-02 8:55 ` [PATCH v3 1/2] aarch64: align address for BTI protection [BZ #26988] Szabolcs Nagy 2020-12-02 8:55 ` Szabolcs Nagy 2020-12-10 18:49 ` Adhemerval Zanella 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 2020-12-02 8:55 ` Szabolcs Nagy 2020-12-10 19:12 ` Adhemerval Zanella 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 2020-11-30 15:56 ` Szabolcs Nagy 2020-12-03 17:30 ` Catalin Marinas 2020-12-03 17:30 ` Catalin Marinas 2020-12-07 20:03 ` Szabolcs Nagy 2020-12-07 20:03 ` Szabolcs Nagy 2020-12-11 17:46 ` Catalin Marinas 2020-12-11 17:46 ` Catalin Marinas
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