Bug#904385: arm64: sigaltstack fails with MINSIGSTKSZ for 32-bit processes
control: notfixed -1 linux/4.18.20-1 control: found -1 4.19.37-6 On 2018-09-26 11:41, Steve McIntyre wrote: > On Wed, Jul 25, 2018 at 04:25:03PM +0100, Steve McIntyre wrote: > >On Mon, Jul 23, 2018 at 09:40:33PM +0200, Aurelien Jarno wrote: > >>control: affects -1 glibc > >>control: found linux/4.17.6-2 > >> > >>On 2018-07-23 21:31, Aurelien Jarno wrote: > >>> Package: src:linux > >>> Version: 4.9.110-1 > >>> Severity: normal > >>> > >>> Dear Maintainer, > >>> > >>> The arm64 kernel allows one to run aarch32 processes on an aarch64 > >>> processor (if it has support for it), using the standard 32/64-bit > >>> syscall compatibility. However this compat layer does not correctly > >>> validate the arguments of the sigaltstack syscall. > >>> > >> > >>I forgot to say that the problem is reproducible with kernel 4.17.6. > > > >Fix proposed in https://lkml.org/lkml/2018/7/25/409 > > At Will's suggestion, I've just tested that patchset locally and it > definitely fixes this problem so I've added a Tested-by: for him. > The fix is composed of two patches, and only the first one went to the stable releases. Therefore both our oldstable and stable kernels used on the build daemons are still buggy. The following one is still missing in at least 4.9 and 4.19: | commit 24951465cbd279f60b1fdc2421b3694405bcff42 | Author: Will Deacon | Date: Wed Sep 5 15:34:43 2018 +0100 | | arm64: compat: Provide definition for COMPAT_SIGMINSTKSZ | | arch/arm/ defines a SIGMINSTKSZ of 2k, so we should use the same value | for compat tasks. | | Cc: Arnd Bergmann | Cc: Dominik Brodowski | Cc: "Eric W. Biederman" | Cc: Andrew Morton | Cc: Al Viro | Cc: Oleg Nesterov | Reviewed-by: Dave Martin | Reported-by: Steve McIntyre | Tested-by: Steve McIntyre <93...@debian.org> | Signed-off-by: Will Deacon | Signed-off-by: Catalin Marinas -- Aurelien Jarno GPG: 4096R/1DDD8C9B aurel...@aurel32.net http://www.aurel32.net
Bug#904385: arm64: sigaltstack fails with MINSIGSTKSZ for 32-bit processes
On Wed, Jul 25, 2018 at 04:25:03PM +0100, Steve McIntyre wrote: >On Mon, Jul 23, 2018 at 09:40:33PM +0200, Aurelien Jarno wrote: >>control: affects -1 glibc >>control: found linux/4.17.6-2 >> >>On 2018-07-23 21:31, Aurelien Jarno wrote: >>> Package: src:linux >>> Version: 4.9.110-1 >>> Severity: normal >>> >>> Dear Maintainer, >>> >>> The arm64 kernel allows one to run aarch32 processes on an aarch64 >>> processor (if it has support for it), using the standard 32/64-bit >>> syscall compatibility. However this compat layer does not correctly >>> validate the arguments of the sigaltstack syscall. >>> >> >>I forgot to say that the problem is reproducible with kernel 4.17.6. > >Fix proposed in https://lkml.org/lkml/2018/7/25/409 At Will's suggestion, I've just tested that patchset locally and it definitely fixes this problem so I've added a Tested-by: for him. -- Steve McIntyre, Cambridge, UK.st...@einval.com There's no sensation to compare with this Suspended animation, A state of bliss
Bug#904385: arm64: sigaltstack fails with MINSIGSTKSZ for 32-bit processes
On Mon, Jul 23, 2018 at 09:40:33PM +0200, Aurelien Jarno wrote: >control: affects -1 glibc >control: found linux/4.17.6-2 > >On 2018-07-23 21:31, Aurelien Jarno wrote: >> Package: src:linux >> Version: 4.9.110-1 >> Severity: normal >> >> Dear Maintainer, >> >> The arm64 kernel allows one to run aarch32 processes on an aarch64 >> processor (if it has support for it), using the standard 32/64-bit >> syscall compatibility. However this compat layer does not correctly >> validate the arguments of the sigaltstack syscall. >> > >I forgot to say that the problem is reproducible with kernel 4.17.6. Fix proposed in https://lkml.org/lkml/2018/7/25/409 -- Steve McIntyre, Cambridge, UK.st...@einval.com You raise the blade, you make the change... You re-arrange me 'til I'm sane...
Bug#904385: arm64: sigaltstack fails with MINSIGSTKSZ for 32-bit processes
control: affects -1 glibc control: found linux/4.17.6-2 On 2018-07-23 21:31, Aurelien Jarno wrote: > Package: src:linux > Version: 4.9.110-1 > Severity: normal > > Dear Maintainer, > > The arm64 kernel allows one to run aarch32 processes on an aarch64 > processor (if it has support for it), using the standard 32/64-bit > syscall compatibility. However this compat layer does not correctly > validate the arguments of the sigaltstack syscall. > I forgot to say that the problem is reproducible with kernel 4.17.6. -- Aurelien Jarno GPG: 4096R/1DDD8C9B aurel...@aurel32.net http://www.aurel32.net
Bug#904385: arm64: sigaltstack fails with MINSIGSTKSZ for 32-bit processes
Package: src:linux
Version: 4.9.110-1
Severity: normal
Dear Maintainer,
The arm64 kernel allows one to run aarch32 processes on an aarch64
processor (if it has support for it), using the standard 32/64-bit
syscall compatibility. However this compat layer does not correctly
validate the arguments of the sigaltstack syscall.
arch/arm64/include/uapi/asm/signal.h defines SIGSTKSZ and MINSIGSTKSZ
as follow:
| #define MINSIGSTKSZ 5120
| #define SIGSTKSZ16384
arch/arm/include/uapi/asm/signal.h defines SIGSTKSZ and MINSIGSTKSZ as
follow:
| #define MINSIGSTKSZ 2048
| #define SIGSTKSZ8192
It seems to be the only 32/64-bit architecture for which those constants
differ. The do_compat_sigaltstack function in kernel/signal.c passes
ss.ss_size to do_sigaltstack unchanged, and the latter validates it
against the native MINSIGSTKSZ.
This causes the glibc test nptl/tst-signal6 to fail, but I guess it can
also affects other packages at runtime. This is also reproducible with
the following simple testcase:
| #include
| #include
| #include
|
| int main(int argc, char *argv[])
| {
| stack_t ss;
|
| ss.ss_sp = malloc(MINSIGSTKSZ);
| if (ss.ss_sp == NULL) {
| perror("malloc");
| exit(EXIT_FAILURE);
| }
|
| ss.ss_size = MINSIGSTKSZ;
| ss.ss_flags = 0;
| if (sigaltstack(, NULL)) {
| perror("sigaltstack");
| exit(EXIT_FAILURE);
| }
|
| return 0;
| }
| $ ./sigaltstack
| sigaltstack: Cannot allocate memory
| $ strace ./sigaltstack
| execve("./sigaltstack", ["./sigaltstack"], [/* 23 vars */]) = 0
| strace: [ Process PID=694 runs in 32 bit mode. ]
| uname({sysname="Linux", nodename="arm64", ...}) = 0
| brk(NULL) = 0x35d000
| brk(0x35dd00) = 0x35dd00
| set_tls(0x35d4c0, 0x78f7c, 0, 0x24, 0x78f6c) = 0
| readlink("/proc/self/exe", "/home/aurel32/sigaltstack", 4096) = 25
| brk(0x37ed00) = 0x37ed00
| brk(0x37f000) = 0x37f000
| access("/etc/ld.so.nohwcap", F_OK) = -1 ENOENT (No such file or
directory)
| sigaltstack({ss_sp=0x35e8b0, ss_flags=0x800 /* SS_??? */, ss_size=67191},
NULL) = -1 ENOMEM (Cannot allocate memory)
| dup(2) = 3
| fcntl64(3, F_GETFL) = 0x20002 (flags O_RDWR|0x2)
| fstat64(3, 0xff96bf28) = 0
| write(3, "sigaltstack: Cannot allocate mem"..., 36sigaltstack: Cannot
allocate memory
| ) = 36
| close(3)= 0
| exit_group(1) = ?
| +++ exited with 1 +++
-- System Information:
Debian Release: 9.5
APT prefers stable-updates
APT policy: (500, 'stable-updates'), (500, 'stable')
Architecture: arm64 (aarch64)
Kernel: Linux 4.9.0-7-arm64 (SMP w/2 CPU cores)
Locale: LANG=fr_FR.UTF-8, LC_CTYPE=fr_FR.UTF-8 (charmap=UTF-8),
LANGUAGE=fr_FR.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
