diff options
| author | Matthew Denton <mpdenton@chromium.org> | 2021-07-21 17:12:27 +0000 |
|---|---|---|
| committer | Michal Klocek <michal.klocek@qt.io> | 2022-06-02 17:42:08 +0000 |
| commit | a7a23ccc69e6756e02583e6871cc37151d89a7c2 (patch) | |
| tree | 07372a20028d37f4f6f756ef0641b11c278dcaef | |
| parent | 7857ff290ab254a5a1fe2e85e146680448b4d46e (diff) | |
[Backport] Linux sandbox: ENOSYS for some statx syscalls
On some platforms, glibc will default to statx for normal stat-family
calls. Unfortunately there's no way to rewrite statx to something safe
using a signal handler. Returning ENOSYS will cause glibc to fallback
to old stat paths.
Backport review link:
https://chromium-review.googlesource.com/c/chromium/src/+/2823150
Task-number: QTBUG-103969
Change-Id: I75c5a52fa9cc142102d38ddbeb38019961ec6b22
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>
3 files changed, 16 insertions, 0 deletions
diff --git a/chromium/sandbox/linux/seccomp-bpf-helpers/baseline_policy.cc b/chromium/sandbox/linux/seccomp-bpf-helpers/baseline_policy.cc index 009197eefbe..5e650d93c4b 100644 --- a/chromium/sandbox/linux/seccomp-bpf-helpers/baseline_policy.cc +++ b/chromium/sandbox/linux/seccomp-bpf-helpers/baseline_policy.cc @@ -271,6 +271,17 @@ ResultExpr EvaluateSyscallImpl(int fs_denied_errno, return RewriteFstatatSIGSYS(fs_denied_errno); } + // The statx syscall is a filesystem syscall, which will be denied below with + // fs_denied_errno. However, on some platforms, glibc will default to statx + // for normal stat-family calls. Unfortunately there's no way to rewrite statx + // to something safe using a signal handler. Returning ENOSYS will cause glibc + // to fallback to old stat paths. + if (sysno == __NR_statx) { + const Arg<int> mask(3); + return If(mask == STATX_BASIC_STATS, Error(ENOSYS)) + .Else(Error(fs_denied_errno)); + } + if (SyscallSets::IsFileSystem(sysno) || SyscallSets::IsCurrentDirectory(sysno)) { return Error(fs_denied_errno); diff --git a/chromium/sandbox/linux/seccomp-bpf-helpers/syscall_sets.cc b/chromium/sandbox/linux/seccomp-bpf-helpers/syscall_sets.cc index 2c7a9e8351b..d1ea8e99a1c 100644 --- a/chromium/sandbox/linux/seccomp-bpf-helpers/syscall_sets.cc +++ b/chromium/sandbox/linux/seccomp-bpf-helpers/syscall_sets.cc @@ -154,6 +154,7 @@ bool SyscallSets::IsFileSystem(int sysno) { (defined(ARCH_CPU_MIPS_FAMILY) && defined(ARCH_CPU_32_BITS)) case __NR_statfs64: #endif + case __NR_statx: // EPERM not a valid errno. case __NR_symlinkat: case __NR_truncate: #if defined(__i386__) || defined(__arm__) || \ diff --git a/chromium/sandbox/linux/system_headers/linux_stat.h b/chromium/sandbox/linux/system_headers/linux_stat.h index 83b89efc75e..e697dd6777e 100644 --- a/chromium/sandbox/linux/system_headers/linux_stat.h +++ b/chromium/sandbox/linux/system_headers/linux_stat.h @@ -161,6 +161,10 @@ struct kernel_stat { #define AT_EMPTY_PATH 0x1000 #endif +#if !defined(STATX_BASIC_STATS) +#define STATX_BASIC_STATS 0x000007ffU +#endif + // On 32-bit systems, we default to the 64-bit stat struct like libc // implementations do. Otherwise we default to the normal stat struct which is // already 64-bit. |