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Sanitizers use wrong version of intercepted symbols #628
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After some discussion in libc-alpha about this POSIX compliance fix, I see that GLIBC should indeed revert back to previous definition of msghdr and cmsghdr and implementation of sendmsg, recvmsg, sendmmsg, recvmmsg due some reasons: * The possible issue where the syscalls wrapper add the compatibility layer is quite limited in scope and range. And kernel current also add some limits to the values on the internal msghdr and cmsghdr fields: - msghdr::msg_iovlen larger than UIO_MAXIOV (1024) returns EMSGSIZE. - msghdr::msg_controllen larger than INT_MAX returns ENOBUFS. * There is a small performance hit for recvmsg/sendmsg/recmmsg which is neglectable, but it is a big hit for sendmmsg since now instead of calling the syscall for the packed structure, GLIBC is calling multiple sendmsg. This defeat the very existence of the syscall. * It currently breaks libsanitizer build on GCC [1] (I fixed on compiler-rt). However the fix is incomplete because it does add any runtime check since libsanitizer currently does not have any facility to intercept symbols with multiple version [2]. This, along with incorret dlsym/dlvsym return for versioned symbol due another bug [3], makes hard to interpose versioned symbols. Also, current approach of fixing GCC PR#71445 leads to half-baked solutions without versioned symbol interposing. This patch basically reverts commits 2f0dc39, 222c2d7, af7f7c7. I decided to not revert abf29ed (Adjust kernel-features.h defaults for recvmsg and sendmsg) mainly because it does not really address the POSIX compliance original issue and also adds some cleanups. Tested on x86, i386, s390, s390x, aarch64, and powerpc64le. [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71445 [2] google/sanitizers#628 [3] https://sourceware.org/bugzilla/show_bug.cgi?id=14932 * conform/data/sys/socket.h-data (msghdr.msg_iovlen): Add xfail-. (msghdr.msg_controllen): Likewise. (cmsghdr.cmsg_len): Likewise. * nptl/Makefile (libpthread-routines): Remove ptw-oldrecvmsg and ptw-oldsendmsg. (CFLAGS-oldrecvmsg.c): Remove rule. (CFLAGS-oldsendmsg.c): Likewise. (CFLAGS-recvmsg.c): Add rule. (CFLAGS-sendmsg.c): Likewise. * sysdeps/unix/sysv/linux/Makefile (sysdep_routines): Remove oldrecvmsg, oldsendmsg, oldrecvmmsg, oldsendmmsg. (CFLAGS-recvmsg.c): Remove rule. (CFLAGS-sendmsg.c): Likewise. (CFLAGS-oldrecvmsg.c): Likewise. (CFLAGS-oldsendmsg.c): Likewise. (CFLAGS-recvmmsg.c): Likewise. * sysdeps/unix/sysv/linux/bits/socket.h (msghdr.msg_iovlen): Revert to kernel defined interfaces. (msghdr.msg_controllen): Likewise. (cmsghdr.cmsg_len): Likewise. (msghdr.__glibc_reserved1): Remove member. (msghdr.__glibc_reserved2): Likewise. (cmsghdr.__glibc_reserved1): Likewise. * sysdeps/unix/sysv/linux/oldrecvmmsg.c: Remove file. * sysdeps/unix/sysv/linux/oldrecvmsg.c: Likewise. * sysdeps/unix/sysv/linux/oldsendmmsg.c: Likewise. * sysdeps/unix/sysv/linux/oldsendmsg.c: Likewise. * sysdeps/unix/sysv/linux/recvmmsg.c: Revert back to previous version. * sysdeps/unix/sysv/linux/recvmsg.c: Likewise. * sysdeps/unix/sysv/linux/sendmmsg.c: Likewise. * sysdeps/unix/sysv/linux/sendmsg.c: Likewise. * sysdeps/unix/sysv/linux/aarch64/Versions [libc] (GLIBC_2.24): Remove recvmsg and sendmsg. * sysdeps/unix/sysv/linux/alpha/Versions [libc] (GLIBC_2.24): Likewise. * sysdeps/unix/sysv/linux/hppa/Versions [libc] (GLIBC_2.24): Likewise. * sysdeps/unix/sysv/linux/i386/Versions [libc] (GLIBC_2.24): Likewise. * sysdeps/unix/sysv/linux/m68k/Versions [libc] (GLIBC_2.24): Likewise. * sysdeps/unix/sysv/linux/microblaze/Versions [libc] (GLIBC_2.24): Likewise. * sysdeps/unix/sysv/linux/mips/mips32/Versions [libc] (GLIBC_2.24): Likewise. * sysdeps/unix/sysv/linux/mips/mips64/n32/Versions [libc] (GLIBC_2.24): Likewise. * sysdeps/unix/sysv/linux/nios2/Versions [libc] (GLIBC_2.24): Likewise. * sysdeps/unix/sysv/linux/powerpc/Versions [libc] (GLIBC_2.24): Likewise. * sysdeps/unix/sysv/linux/powerpc/powerpc64/Versions [libc] (GLIBC_2.24): Likewise. * sysdeps/unix/sysv/linux/s390/s390-32/Versions [libc] (GLIBC_2.24): Likewise. * sysdeps/unix/sysv/linux/s390/s390-64/Versions [libc] (GLIBC_2.24): Likewise. * sysdeps/unix/sysv/linux/sh/Versions [libc] (GLIBC_2.24): Likewise. * sysdeps/unix/sysv/linux/sparc/Versions [libc] (GLIBC_2.24): Likewise. * sysdeps/unix/sysv/linux/sparc/sparc64/Versions [libc] (GLIBC_2.24): Likewise. * sysdeps/unix/sysv/linux/tile/Versions [libc] (GLIBC_2.24): Likewise. * sysdeps/unix/sysv/linux/x86_64/Versions [libc] (GLIBC_2.24): Likewise. * sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/Versions: Remove file * sysdeps/unix/sysv/linux/x86_64/64/Versions: Likewise. * sysdeps/unix/sysv/linux/mips/mips64/n64/Versions: Likewise. * sysdeps/unix/sysv/linux/aarch64/libc.abilist: Remove new 2.24 version for {recv,send,recm,sendm}msg. * sysdeps/unix/sysv/linux/alpha/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/arm/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/hppa/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/i386/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/ia64/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/m68k/coldfire/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/m68k/m680x0/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/microblaze/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/mips/mips32/fpu/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/mips/mips32/nofpu/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/mips/mips64/n32/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/mips/mips64/n64/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/powerpc/powerpc64/libc-le.abilist: Likewise. * sysdeps/unix/sysv/linux/powerpc/powerpc64/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/s390/s390-32/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/s390/s390-64/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/nios2/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/sh/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/sparc/sparc32/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/sparc/sparc64/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/tile/tilepro/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/x86_64/64/libc.abilist: Likewise. * sysdeps/unix/sysv/linux/x86_64/x32/libc.abilist: Likewise.
@kcc: Is this something we intend to fix at some point? |
dunno, nobody complained recently. |
This is still a serious issue with Asan interceptors... |
@yugr would you like to elaborate? |
Glibc exports legacy versions of standard APIs (with different ABIs) so that applications compiled against legacy Glibc's keep working. Asan implements only the latest ABI and does not assign version information to interceptor so it'll intercept calls to legacy ABIs as well. Calling interceptor from code that was compiled against older Glibc will result in runtime crash. |
See also #778 |
let's keep it open in case someone wants to fix this (not me though). |
This is mostly an i386 problem, where glibc has a long history of changes. For example, pthread_mutex_t layout has changed (AFAIR more than once). But that platform is almost gone by now. As x86_64 matures, we will surely see versioned symbols for common libc functions there as well. |
This is a big deal for FreeBSD! Many languages, most prominently Rust (well, the libc crate) by default link to pre-ino64 symbols like |
Unfortunately, sanitizers do not support versioned symbols[1], so they break filesystem access via the legacy, pre-ino64 ABI. To use sanitizers on FreeBSD >= 12, we need to build the libc crate with LIBC_CI=1 to use the new ABI -- including the libc used for std. But that removes the st_lspare field std was expecting for the deprecated metadata extension. Add a way to skip that field to allow the build to work. [1]: google/sanitizers#628
…-obk Add sanitizer support on FreeBSD Restarting rust-lang#47337. Everything is better now, no more weird llvm problems, well not everything: Unfortunately, the sanitizers don't have proper support for versioned symbols (google/sanitizers#628), so `libc`'s usage of `stat@FBSD_1.0` and so on explodes, e.g. in calling `std::fs::metadata`. Building std (now easy thanks to cargo `-Zbuild-std`) and libc with `freebsd12/13` config via the `LIBC_CI=1` env variable is a good workaround… ``` LIBC_CI=1 RUSTFLAGS="-Z sanitizer=address" cargo +san-test -Zbuild-std run --target x86_64-unknown-freebsd --verbose ``` …*except* std won't build because there's no `st_lspare` in the ino64 version of the struct, so an std patch is required: ```diff --- i/src/libstd/os/freebsd/fs.rs +++ w/src/libstd/os/freebsd/fs.rs @@ -66,8 +66,6 @@ pub trait MetadataExt { fn st_flags(&self) -> u32; #[stable(feature = "metadata_ext2", since = "1.8.0")] fn st_gen(&self) -> u32; - #[stable(feature = "metadata_ext2", since = "1.8.0")] - fn st_lspare(&self) -> u32; } #[stable(feature = "metadata_ext", since = "1.1.0")] @@ -136,7 +134,4 @@ impl MetadataExt for Metadata { fn st_flags(&self) -> u32 { self.as_inner().as_inner().st_flags as u32 } - fn st_lspare(&self) -> u32 { - self.as_inner().as_inner().st_lspare as u32 - } } ``` I guess std could like.. detect that `libc` isn't built for the old ABI, and replace the implementation of `st_lspare` with a panic?
Unfortunately, sanitizers do not support versioned symbols[1], so they break filesystem access via the legacy, pre-ino64 ABI. To use sanitizers on FreeBSD >= 12, we need to build the libc crate with LIBC_CI=1 to use the new ABI -- including the libc used for std. But that removes the st_lspare field std was expecting for the deprecated metadata extension. Add a way to skip that field to allow the build to work. [1]: google/sanitizers#628
Add sanitizer support on FreeBSD Restarting rust-lang#47337. Everything is better now, no more weird llvm problems, well not everything: Unfortunately, the sanitizers don't have proper support for versioned symbols (google/sanitizers#628), so `libc`'s usage of `stat@FBSD_1.0` and so on explodes, e.g. in calling `std::fs::metadata`. Building std (now easy thanks to cargo `-Zbuild-std`) and libc with `freebsd12/13` config via the `LIBC_CI=1` env variable is a good workaround… ``` LIBC_CI=1 RUSTFLAGS="-Z sanitizer=address" cargo +san-test -Zbuild-std run --target x86_64-unknown-freebsd --verbose ``` …*except* std won't build because there's no `st_lspare` in the ino64 version of the struct, so an std patch is required: ```diff --- i/src/libstd/os/freebsd/fs.rs +++ w/src/libstd/os/freebsd/fs.rs @@ -66,8 +66,6 @@ pub trait MetadataExt { fn st_flags(&self) -> u32; #[stable(feature = "metadata_ext2", since = "1.8.0")] fn st_gen(&self) -> u32; - #[stable(feature = "metadata_ext2", since = "1.8.0")] - fn st_lspare(&self) -> u32; } #[stable(feature = "metadata_ext", since = "1.1.0")] @@ -136,7 +134,4 @@ impl MetadataExt for Metadata { fn st_flags(&self) -> u32 { self.as_inner().as_inner().st_flags as u32 } - fn st_lspare(&self) -> u32 { - self.as_inner().as_inner().st_lspare as u32 - } } ``` I guess std could like.. detect that `libc` isn't built for the old ABI, and replace the implementation of `st_lspare` with a panic?
fmemopen(2) is broken with address and memory sanitizer, see google/sanitizers#627 and google/sanitizers#628.
fmemopen(2) is broken with address and memory sanitizer, see google/sanitizers#628.
fmemopen(2) is broken with address and memory sanitizer, see google/sanitizers#628.
fmemopen(2) is broken with address and memory sanitizer, see google/sanitizers#628.
Because intercepted symbols are reexported without version information, wrong version of a symbol could be used during runtime. An example would be fmemopen in glibc2.22 (#627)
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