Date: Sat, 07 Feb 2026 22:15:09 +0000 From: Rick Macklem <rmacklem@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: 110f2567cb51 - main - linux_file.c: Fix handling of NFS getdents() emulation Message-ID: <6987b96d.1bcdf.6467a437@gitrepo.freebsd.org>
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The branch main has been updated by rmacklem: URL: https://cgit.FreeBSD.org/src/commit/?id=110f2567cb51f1eeddbd5d9937000ad64f6dc746 commit 110f2567cb51f1eeddbd5d9937000ad64f6dc746 Author: Rick Macklem <rmacklem@FreeBSD.org> AuthorDate: 2026-02-07 22:12:55 +0000 Commit: Rick Macklem <rmacklem@FreeBSD.org> CommitDate: 2026-02-07 22:12:55 +0000 linux_file.c: Fix handling of NFS getdents() emulation Bugzilla PR#292282 reports a problem, where a Linux binary running in the Linuxulator gets bogus entries in a readdir()/getdents() reply when the directory is an NFS mount. This appears to be caused by the NFS client including entries with d_fileno == 0, which are always ignored by BSD, but are not ignored by Linux. This patch filters out the "d_fileno == 0" entries and the reporter of the bugzilla PR notes that it fixes the problem for him. It could be argued that the NFS client should filter out the "d_fileno == 0" entries, but the NFS client readdir code is "fragile" and any change to it runs a significant risk of causing regression type problems. As such, since the LInuxulator is already broken for this case, it seems safer to filter them out there. PR: 292282 Tested by: Jerry Williams <jwillia3@proton.me> Reviewed by: markj MFC after: 2 weeks Differential Revision: https://reviews.freebsd.org/D54679 --- sys/compat/linux/linux_file.c | 178 ++++++++++++++++++++++++++---------------- 1 file changed, 110 insertions(+), 68 deletions(-) diff --git a/sys/compat/linux/linux_file.c b/sys/compat/linux/linux_file.c index daddafa325ad..96326b894d05 100644 --- a/sys/compat/linux/linux_file.c +++ b/sys/compat/linux/linux_file.c @@ -398,12 +398,50 @@ struct l_dirent64 { roundup(offsetof(struct l_dirent64, d_name) + (namlen) + 1, \ sizeof(uint64_t)) +/* + * Do kern_getdirentries() and then skip over any invalid entries. + * (Repeat, if there are no valid entries.) + * Adjust bufp and lenp. + */ +static int +linux_getdirentries(struct thread *td, int fd, caddr_t *bufp, int buflen, + off_t *basep, int *lenp) +{ + struct dirent *bdp; + caddr_t buf; + int error, len; + + /* Loop around until a valid entry is found or at EOF. */ + for (;;) { + error = kern_getdirentries(td, fd, *bufp, buflen, + basep, NULL, UIO_SYSSPACE); + if (error != 0) + return (error); + len = td->td_retval[0]; + if (len == 0) { + *lenp = 0; + return (0); + } + buf = *bufp; + while (len > 0) { + bdp = (struct dirent *)buf; + if (bdp->d_fileno != 0) { + *bufp = buf; + *lenp = len; + return (0); + } + buf += bdp->d_reclen; + len -= bdp->d_reclen; + } + } +} + #ifdef LINUX_LEGACY_SYSCALLS int linux_getdents(struct thread *td, struct linux_getdents_args *args) { struct dirent *bdp; - caddr_t inp, buf; /* BSD-format */ + caddr_t inp, buf, bufsav; /* BSD-format */ int len, reclen; /* BSD-format */ caddr_t outp; /* Linux-format */ int resid, linuxreclen; /* Linux-format */ @@ -413,11 +451,11 @@ linux_getdents(struct thread *td, struct linux_getdents_args *args) int buflen, error; size_t retval; - buflen = min(args->count, MAXBSIZE); - buf = malloc(buflen, M_LINUX, M_WAITOK); + buflen = min(roundup2(args->count, DEV_BSIZE), MAXBSIZE); + bufsav = buf = malloc(buflen, M_LINUX, M_WAITOK); - error = kern_getdirentries(td, args->fd, buf, buflen, - &base, NULL, UIO_SYSSPACE); + error = linux_getdirentries(td, args->fd, &buf, buflen, + &base, &len); if (error != 0) { error = linux_getdents_error(td, args->fd, error); goto out1; @@ -425,7 +463,6 @@ linux_getdents(struct thread *td, struct linux_getdents_args *args) lbuf = malloc(LINUX_RECLEN(LINUX_NAME_MAX), M_LINUX, M_WAITOK | M_ZERO); - len = td->td_retval[0]; inp = buf; outp = (caddr_t)args->dent; resid = args->count; @@ -434,44 +471,47 @@ linux_getdents(struct thread *td, struct linux_getdents_args *args) while (len > 0) { bdp = (struct dirent *) inp; reclen = bdp->d_reclen; - linuxreclen = LINUX_RECLEN(bdp->d_namlen); - /* - * No more space in the user supplied dirent buffer. - * Return EINVAL. - */ - if (resid < linuxreclen) { - error = EINVAL; - goto out; + /* Copy a valid entry out. */ + if (bdp->d_fileno != 0) { + linuxreclen = LINUX_RECLEN(bdp->d_namlen); + /* + * No more space in the user supplied dirent buffer. + * Return EINVAL. + */ + if (resid < linuxreclen) { + error = EINVAL; + goto out; + } + + linux_dirent = (struct l_dirent*)lbuf; + linux_dirent->d_ino = bdp->d_fileno; + linux_dirent->d_off = bdp->d_off; + linux_dirent->d_reclen = linuxreclen; + /* + * Copy d_type to last byte of l_dirent buffer + */ + lbuf[linuxreclen - 1] = bdp->d_type; + strlcpy(linux_dirent->d_name, bdp->d_name, + linuxreclen - offsetof(struct l_dirent, d_name)-1); + error = copyout(linux_dirent, outp, linuxreclen); + if (error != 0) + goto out; + retval += linuxreclen; + outp += linuxreclen; + resid -= linuxreclen; } - linux_dirent = (struct l_dirent*)lbuf; - linux_dirent->d_ino = bdp->d_fileno; - linux_dirent->d_off = bdp->d_off; - linux_dirent->d_reclen = linuxreclen; - /* - * Copy d_type to last byte of l_dirent buffer - */ - lbuf[linuxreclen - 1] = bdp->d_type; - strlcpy(linux_dirent->d_name, bdp->d_name, - linuxreclen - offsetof(struct l_dirent, d_name)-1); - error = copyout(linux_dirent, outp, linuxreclen); - if (error != 0) - goto out; - inp += reclen; base += reclen; len -= reclen; - retval += linuxreclen; - outp += linuxreclen; - resid -= linuxreclen; } td->td_retval[0] = retval; out: free(lbuf, M_LINUX); out1: - free(buf, M_LINUX); + free(bufsav, M_LINUX); return (error); } #endif @@ -480,7 +520,7 @@ int linux_getdents64(struct thread *td, struct linux_getdents64_args *args) { struct dirent *bdp; - caddr_t inp, buf; /* BSD-format */ + caddr_t inp, buf, bufsav; /* BSD-format */ int len, reclen; /* BSD-format */ caddr_t outp; /* Linux-format */ int resid, linuxreclen; /* Linux-format */ @@ -489,11 +529,11 @@ linux_getdents64(struct thread *td, struct linux_getdents64_args *args) int buflen, error; size_t retval; - buflen = min(args->count, MAXBSIZE); - buf = malloc(buflen, M_LINUX, M_WAITOK); + buflen = min(roundup2(args->count, DEV_BSIZE), MAXBSIZE); + bufsav = buf = malloc(buflen, M_LINUX, M_WAITOK); - error = kern_getdirentries(td, args->fd, buf, buflen, - &base, NULL, UIO_SYSSPACE); + error = linux_getdirentries(td, args->fd, &buf, buflen, + &base, &len); if (error != 0) { error = linux_getdents_error(td, args->fd, error); goto out1; @@ -502,7 +542,6 @@ linux_getdents64(struct thread *td, struct linux_getdents64_args *args) linux_dirent64 = malloc(LINUX_RECLEN64(LINUX_NAME_MAX), M_LINUX, M_WAITOK | M_ZERO); - len = td->td_retval[0]; inp = buf; outp = (caddr_t)args->dirent; resid = args->count; @@ -511,40 +550,43 @@ linux_getdents64(struct thread *td, struct linux_getdents64_args *args) while (len > 0) { bdp = (struct dirent *) inp; reclen = bdp->d_reclen; - linuxreclen = LINUX_RECLEN64(bdp->d_namlen); - /* - * No more space in the user supplied dirent buffer. - * Return EINVAL. - */ - if (resid < linuxreclen) { - error = EINVAL; - goto out; + /* Copy a valid entry out. */ + if (bdp->d_fileno != 0) { + linuxreclen = LINUX_RECLEN64(bdp->d_namlen); + /* + * No more space in the user supplied dirent buffer. + * Return EINVAL. + */ + if (resid < linuxreclen) { + error = EINVAL; + goto out; + } + + linux_dirent64->d_ino = bdp->d_fileno; + linux_dirent64->d_off = bdp->d_off; + linux_dirent64->d_reclen = linuxreclen; + linux_dirent64->d_type = bdp->d_type; + strlcpy(linux_dirent64->d_name, bdp->d_name, + linuxreclen - offsetof(struct l_dirent64, d_name)); + error = copyout(linux_dirent64, outp, linuxreclen); + if (error != 0) + goto out; + retval += linuxreclen; + outp += linuxreclen; + resid -= linuxreclen; } - linux_dirent64->d_ino = bdp->d_fileno; - linux_dirent64->d_off = bdp->d_off; - linux_dirent64->d_reclen = linuxreclen; - linux_dirent64->d_type = bdp->d_type; - strlcpy(linux_dirent64->d_name, bdp->d_name, - linuxreclen - offsetof(struct l_dirent64, d_name)); - error = copyout(linux_dirent64, outp, linuxreclen); - if (error != 0) - goto out; - inp += reclen; base += reclen; len -= reclen; - retval += linuxreclen; - outp += linuxreclen; - resid -= linuxreclen; } td->td_retval[0] = retval; out: free(linux_dirent64, M_LINUX); out1: - free(buf, M_LINUX); + free(bufsav, M_LINUX); return (error); } @@ -553,22 +595,22 @@ int linux_readdir(struct thread *td, struct linux_readdir_args *args) { struct dirent *bdp; - caddr_t buf; /* BSD-format */ + caddr_t buf, bufsav; /* BSD-format */ int linuxreclen; /* Linux-format */ off_t base; struct l_dirent *linux_dirent; /* Linux-format */ - int buflen, error; + int buflen, error, len; - buflen = sizeof(*bdp); - buf = malloc(buflen, M_LINUX, M_WAITOK); + buflen = DEV_BSIZE; + bufsav = buf = malloc(buflen, M_LINUX, M_WAITOK); - error = kern_getdirentries(td, args->fd, buf, buflen, - &base, NULL, UIO_SYSSPACE); + error = linux_getdirentries(td, args->fd, &buf, buflen, + &base, &len); if (error != 0) { error = linux_getdents_error(td, args->fd, error); goto out; } - if (td->td_retval[0] == 0) + if (len == 0) goto out; linux_dirent = malloc(LINUX_RECLEN(LINUX_NAME_MAX), M_LINUX, @@ -588,7 +630,7 @@ linux_readdir(struct thread *td, struct linux_readdir_args *args) free(linux_dirent, M_LINUX); out: - free(buf, M_LINUX); + free(bufsav, M_LINUX); return (error); } #endif /* __i386__ || (__amd64__ && COMPAT_LINUX32) */home | help
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