Date: Mon, 10 Jul 2023 14:14:12 GMT From: Alan Somers <asomers@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: 6c049996ec29 - main - During F_SETFL, don't change file flags on error Message-ID: <202307101414.36AEECfx038954@gitrepo.freebsd.org>
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The branch main has been updated by asomers: URL: https://cgit.FreeBSD.org/src/commit/?id=6c049996ec29bad4a913b019a28f211ab84b0d3d commit 6c049996ec29bad4a913b019a28f211ab84b0d3d Author: Alan Somers <asomers@FreeBSD.org> AuthorDate: 2023-07-09 20:48:10 +0000 Commit: Alan Somers <asomers@FreeBSD.org> CommitDate: 2023-07-10 14:13:58 +0000 During F_SETFL, don't change file flags on error Previously, even if the FIONBIO or FIOASYNC ioctl failed, the file's f_flags variable would still be changed. Now, kern_fcntl will restore the original flags if the ioctl fails. PR: 265736 Reported by: Yuval Pavel Zholkover <paulzhol@gmail.com> MFC after: 2 weeks Reviewed by: kib Differential Revision: https://reviews.freebsd.org/D40955 --- sys/kern/kern_descrip.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) diff --git a/sys/kern/kern_descrip.c b/sys/kern/kern_descrip.c index 908c3352514b..ad1b86a0c76c 100644 --- a/sys/kern/kern_descrip.c +++ b/sys/kern/kern_descrip.c @@ -495,7 +495,7 @@ kern_fcntl(struct thread *td, int fd, int cmd, intptr_t arg) struct vnode *vp; struct mount *mp; struct kinfo_file *kif; - int error, flg, kif_sz, seals, tmp; + int error, flg, kif_sz, seals, tmp, got_set, got_cleared; uint64_t bsize; off_t foffset; @@ -573,12 +573,12 @@ kern_fcntl(struct thread *td, int fd, int cmd, intptr_t arg) tmp &= ~FCNTLFLAGS; tmp |= FFLAGS(arg & ~O_ACCMODE) & FCNTLFLAGS; } while (atomic_cmpset_int(&fp->f_flag, flg, tmp) == 0); + got_set = tmp & ~flg; + got_cleared = flg & ~tmp; tmp = fp->f_flag & FNONBLOCK; error = fo_ioctl(fp, FIONBIO, &tmp, td->td_ucred, td); - if (error != 0) { - fdrop(fp, td); - break; - } + if (error != 0) + goto revert_f_setfl; tmp = fp->f_flag & FASYNC; error = fo_ioctl(fp, FIOASYNC, &tmp, td->td_ucred, td); if (error == 0) { @@ -588,6 +588,13 @@ kern_fcntl(struct thread *td, int fd, int cmd, intptr_t arg) atomic_clear_int(&fp->f_flag, FNONBLOCK); tmp = 0; (void)fo_ioctl(fp, FIONBIO, &tmp, td->td_ucred, td); +revert_f_setfl: + do { + tmp = flg = fp->f_flag; + tmp &= ~FCNTLFLAGS; + tmp |= got_cleared; + tmp &= ~got_set; + } while (atomic_cmpset_int(&fp->f_flag, flg, tmp) == 0); fdrop(fp, td); break;
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