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D49440.id152540.diff
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D49440.id152540.diff
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diff --git a/sys/kern/vfs_syscalls.c b/sys/kern/vfs_syscalls.c
--- a/sys/kern/vfs_syscalls.c
+++ b/sys/kern/vfs_syscalls.c
@@ -4945,11 +4945,11 @@
int error;
size_t retlen;
void *rl_rcookie, *rl_wcookie;
- off_t savinoff, savoutoff;
+ off_t inoff, outoff, savinoff, savoutoff;
infp = outfp = NULL;
rl_rcookie = rl_wcookie = NULL;
- savinoff = -1;
+ savinoff = -1; /* sentinel value for error handling */
error = 0;
retlen = 0;
@@ -4991,13 +4991,41 @@
goto out;
}
- /* Set the offset pointers to the correct place. */
- if (inoffp == NULL)
- inoffp = &infp->f_offset;
- if (outoffp == NULL)
- outoffp = &outfp->f_offset;
- savinoff = *inoffp;
- savoutoff = *outoffp;
+ /*
+ * Figure out which file offsets we're reading from and writing to.
+ * If the offsets come from the file descriptions, we need to lock them,
+ * and locking both offsets requires a loop to avoid deadlocks.
+ */
+ if (inoffp != NULL && outoffp != NULL) {
+ inoff = *inoffp;
+ outoff = *outoffp;
+ } else if (inoffp != NULL) {
+ inoff = *inoffp;
+ outoff = foffset_lock(outfp, 0);
+ } else if (outoffp != NULL) {
+ outoff = *outoffp;
+ inoff = foffset_lock(infp, 0);
+ } else {
+ if (infp == outfp) {
+ /*
+ * Overlapping ranges are not allowed. A more thorough
+ * check is below, but we must not lock the same offset
+ * twice.
+ */
+ error = EINVAL;
+ goto out;
+ }
+ for (;;) {
+ inoff = foffset_lock(infp, 0);
+ if (foffset_trylock(outfp, 0, &outoff) == 0)
+ break;
+ foffset_unlock(infp, inoff, FOF_NOUPDATE);
+ (void)foffset_lock(outfp, 0);
+ foffset_unlock(outfp, outoff, FOF_NOUPDATE);
+ }
+ }
+ savinoff = inoff;
+ savoutoff = outoff;
invp = infp->f_vnode;
outvp = outfp->f_vnode;
@@ -5017,8 +5045,8 @@
* overlap.
*/
if (invp == outvp) {
- if ((savinoff <= savoutoff && savinoff + len > savoutoff) ||
- (savinoff > savoutoff && savoutoff + len > savinoff)) {
+ if ((inoff <= outoff && inoff + len > outoff) ||
+ (inoff > outoff && outoff + len > inoff)) {
error = EINVAL;
goto out;
}
@@ -5027,28 +5055,36 @@
/* Range lock the byte ranges for both invp and outvp. */
for (;;) {
- rl_wcookie = vn_rangelock_wlock(outvp, *outoffp, *outoffp +
- len);
- rl_rcookie = vn_rangelock_tryrlock(invp, *inoffp, *inoffp +
- len);
+ rl_wcookie = vn_rangelock_wlock(outvp, outoff, outoff + len);
+ rl_rcookie = vn_rangelock_tryrlock(invp, inoff, inoff + len);
if (rl_rcookie != NULL)
break;
vn_rangelock_unlock(outvp, rl_wcookie);
- rl_rcookie = vn_rangelock_rlock(invp, *inoffp, *inoffp + len);
+ rl_rcookie = vn_rangelock_rlock(invp, inoff, inoff + len);
vn_rangelock_unlock(invp, rl_rcookie);
}
retlen = len;
- error = vn_copy_file_range(invp, inoffp, outvp, outoffp, &retlen,
+ error = vn_copy_file_range(invp, &inoff, outvp, &outoff, &retlen,
flags, infp->f_cred, outfp->f_cred, td);
out:
if (rl_rcookie != NULL)
vn_rangelock_unlock(invp, rl_rcookie);
if (rl_wcookie != NULL)
vn_rangelock_unlock(outvp, rl_wcookie);
- if (savinoff != -1 && (error == EINTR || error == ERESTART)) {
- *inoffp = savinoff;
- *outoffp = savoutoff;
+ if (savinoff != -1) {
+ if (error == EINTR || error == ERESTART) {
+ inoff = savinoff;
+ outoff = savoutoff;
+ }
+ if (inoffp == NULL)
+ foffset_unlock(infp, inoff, 0);
+ else
+ *inoffp = inoff;
+ if (outoffp == NULL)
+ foffset_unlock(outfp, outoff, 0);
+ else
+ *outoffp = outoff;
}
if (outfp != NULL)
fdrop(outfp, td);

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