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| author | Rich Felker <dalias@aerifal.cx> | 2020-03-13 16:27:10 -0400 |
|---|---|---|
| committer | Rich Felker <dalias@aerifal.cx> | 2020-03-14 21:23:37 -0400 |
| commit | 2b2c8aafce9d80f9d58652643538f4d58e82b856 (patch) | |
| tree | 12fe8c1190cef866cf469777ca00fd3b7252a072 /src/ipc/semctl.c | |
| parent | 5db475f0b987bfa7935a117aac81e14a98de34fb (diff) | |
| download | musl-2b2c8aafce9d80f9d58652643538f4d58e82b856.tar.gz musl-2b2c8aafce9d80f9d58652643538f4d58e82b856.tar.bz2 musl-2b2c8aafce9d80f9d58652643538f4d58e82b856.tar.xz musl-2b2c8aafce9d80f9d58652643538f4d58e82b856.zip | |
fix corrupt sysvipc timestamps on 32-bit archs with old kernels
kernel commit 4693916846269d633a3664586650dbfac2c5562f (first included
in release v4.14) silently fixed a bug whereby the reserved space
(which was later used for high bits of time) in IPC_STAT structures
was left untouched rather than zeroed. this means that a caller that
wants to read the high bits needs to pre-zero the memory.
since it's not clear that these operations are permitted to modify the
destination buffer on failure, use a temp buffer and copy back to the
caller's buffer on success.
Diffstat (limited to 'src/ipc/semctl.c')
| -rw-r--r-- | src/ipc/semctl.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/src/ipc/semctl.c b/src/ipc/semctl.c index ed982747..bbb97d7a 100644 --- a/src/ipc/semctl.c +++ b/src/ipc/semctl.c @@ -28,6 +28,14 @@ int semctl(int id, int num, int cmd, ...) arg = va_arg(ap, union semun); va_end(ap); } +#if IPC_TIME64 + struct semid_ds out, *orig; + if (cmd&IPC_TIME64) { + out = (struct semid_ds){0}; + orig = arg.buf; + arg.buf = &out; + } +#endif #ifdef SYSCALL_IPC_BROKEN_MODE struct semid_ds tmp; if (cmd == IPC_SET) { @@ -51,6 +59,8 @@ int semctl(int id, int num, int cmd, ...) #endif #if IPC_TIME64 if (r >= 0 && (cmd&IPC_TIME64)) { + arg.buf = orig; + *arg.buf = out; IPC_HILO(arg.buf, sem_otime); IPC_HILO(arg.buf, sem_ctime); } |