From d2ceb7e57086750ea6198a31fd942d98099a0786 Mon Sep 17 00:00:00 2001 From: Benjamin Coddington Date: Wed, 6 Feb 2019 06:09:43 -0500 Subject: NFS: Don't use page_file_mapping after removing the page If nfs_page_async_flush() removes the page from the mapping, then we can't use page_file_mapping() on it as nfs_updatepate() is wont to do when receiving an error. Instead, push the mapping to the stack before the page is possibly truncated. Fixes: 8fc75bed96bb ("NFS: Fix up return value on fatal errors in nfs_page_async_flush()") Signed-off-by: Benjamin Coddington Signed-off-by: Anna Schumaker --- fs/nfs/write.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) (limited to 'fs') diff --git a/fs/nfs/write.c b/fs/nfs/write.c index f12cb31a41e5..d09c9f878141 100644 --- a/fs/nfs/write.c +++ b/fs/nfs/write.c @@ -238,9 +238,9 @@ out: } /* A writeback failed: mark the page as bad, and invalidate the page cache */ -static void nfs_set_pageerror(struct page *page) +static void nfs_set_pageerror(struct address_space *mapping) { - nfs_zap_mapping(page_file_mapping(page)->host, page_file_mapping(page)); + nfs_zap_mapping(mapping->host, mapping); } /* @@ -994,7 +994,7 @@ static void nfs_write_completion(struct nfs_pgio_header *hdr) nfs_list_remove_request(req); if (test_bit(NFS_IOHDR_ERROR, &hdr->flags) && (hdr->good_bytes < bytes)) { - nfs_set_pageerror(req->wb_page); + nfs_set_pageerror(page_file_mapping(req->wb_page)); nfs_context_set_write_error(req->wb_context, hdr->error); goto remove_req; } @@ -1348,7 +1348,8 @@ int nfs_updatepage(struct file *file, struct page *page, unsigned int offset, unsigned int count) { struct nfs_open_context *ctx = nfs_file_open_context(file); - struct inode *inode = page_file_mapping(page)->host; + struct address_space *mapping = page_file_mapping(page); + struct inode *inode = mapping->host; int status = 0; nfs_inc_stats(inode, NFSIOS_VFSUPDATEPAGE); @@ -1366,7 +1367,7 @@ int nfs_updatepage(struct file *file, struct page *page, status = nfs_writepage_setup(ctx, page, offset, count); if (status < 0) - nfs_set_pageerror(page); + nfs_set_pageerror(mapping); else __set_page_dirty_nobuffers(page); out: -- cgit v1.2.3 From 3bf6b57ec2ec945e5a6edf5c202a754f1e852ecd Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Thu, 14 Feb 2019 12:33:19 -0500 Subject: Revert "nfsd4: return default lease period" This reverts commit d6ebf5088f09472c1136cd506bdc27034a6763f8. I forgot that the kernel's default lease period should never be decreased! After a kernel upgrade, the kernel has no way of knowing on its own what the previous lease time was. Unless userspace tells it otherwise, it will assume the previous lease period was the same. So if we decrease this value in a kernel upgrade, we end up enforcing a grace period that's too short, and clients will fail to reclaim state in time. Symptoms may include EIO and log messages like "NFS: nfs4_reclaim_open_state: Lock reclaim failed!" There was no real justification for the lease period decrease anyway. Reported-by: Donald Buczek Fixes: d6ebf5088f09 "nfsd4: return default lease period" Cc: stable@vger.kernel.org Signed-off-by: J. Bruce Fields --- fs/nfsd/nfsctl.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'fs') diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c index b33f9785b756..72a7681f4046 100644 --- a/fs/nfsd/nfsctl.c +++ b/fs/nfsd/nfsctl.c @@ -1239,8 +1239,8 @@ static __net_init int nfsd_init_net(struct net *net) retval = nfsd_idmap_init(net); if (retval) goto out_idmap_error; - nn->nfsd4_lease = 45; /* default lease time */ - nn->nfsd4_grace = 45; + nn->nfsd4_lease = 90; /* default lease time */ + nn->nfsd4_grace = 90; nn->somebody_reclaimed = false; nn->clverifier_counter = prandom_u32(); nn->clientid_counter = prandom_u32(); -- cgit v1.2.3 From b5372fe5dc84235dbe04998efdede3c4daa866a9 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Mon, 18 Feb 2019 16:36:48 -0800 Subject: exec: load_script: Do not exec truncated interpreter path Commit 8099b047ecc4 ("exec: load_script: don't blindly truncate shebang string") was trying to protect against a confused exec of a truncated interpreter path. However, it was overeager and also refused to truncate arguments as well, which broke userspace, and it was reverted. This attempts the protection again, but allows arguments to remain truncated. In an effort to improve readability, helper functions and comments have been added. Co-developed-by: Linus Torvalds Signed-off-by: Kees Cook Cc: Andrew Morton Cc: Oleg Nesterov Cc: Samuel Dionne-Riel Cc: Richard Weinberger Cc: Graham Christensen Cc: Michal Hocko Signed-off-by: Linus Torvalds --- fs/binfmt_script.c | 57 +++++++++++++++++++++++++++++++++++++++++++++--------- 1 file changed, 48 insertions(+), 9 deletions(-) (limited to 'fs') diff --git a/fs/binfmt_script.c b/fs/binfmt_script.c index 7cde3f46ad26..e996174cbfc0 100644 --- a/fs/binfmt_script.c +++ b/fs/binfmt_script.c @@ -14,13 +14,30 @@ #include #include +static inline bool spacetab(char c) { return c == ' ' || c == '\t'; } +static inline char *next_non_spacetab(char *first, const char *last) +{ + for (; first <= last; first++) + if (!spacetab(*first)) + return first; + return NULL; +} +static inline char *next_terminator(char *first, const char *last) +{ + for (; first <= last; first++) + if (spacetab(*first) || !*first) + return first; + return NULL; +} + static int load_script(struct linux_binprm *bprm) { const char *i_arg, *i_name; - char *cp; + char *cp, *buf_end; struct file *file; int retval; + /* Not ours to exec if we don't start with "#!". */ if ((bprm->buf[0] != '#') || (bprm->buf[1] != '!')) return -ENOEXEC; @@ -33,18 +50,40 @@ static int load_script(struct linux_binprm *bprm) if (bprm->interp_flags & BINPRM_FLAGS_PATH_INACCESSIBLE) return -ENOENT; - /* - * This section does the #! interpretation. - * Sorta complicated, but hopefully it will work. -TYT - */ - + /* Release since we are not mapping a binary into memory. */ allow_write_access(bprm->file); fput(bprm->file); bprm->file = NULL; - bprm->buf[BINPRM_BUF_SIZE - 1] = '\0'; - if ((cp = strchr(bprm->buf, '\n')) == NULL) - cp = bprm->buf+BINPRM_BUF_SIZE-1; + /* + * This section handles parsing the #! line into separate + * interpreter path and argument strings. We must be careful + * because bprm->buf is not yet guaranteed to be NUL-terminated + * (though the buffer will have trailing NUL padding when the + * file size was smaller than the buffer size). + * + * We do not want to exec a truncated interpreter path, so either + * we find a newline (which indicates nothing is truncated), or + * we find a space/tab/NUL after the interpreter path (which + * itself may be preceded by spaces/tabs). Truncating the + * arguments is fine: the interpreter can re-read the script to + * parse them on its own. + */ + buf_end = bprm->buf + sizeof(bprm->buf) - 1; + cp = strnchr(bprm->buf, sizeof(bprm->buf), '\n'); + if (!cp) { + cp = next_non_spacetab(bprm->buf + 2, buf_end); + if (!cp) + return -ENOEXEC; /* Entire buf is spaces/tabs */ + /* + * If there is no later space/tab/NUL we must assume the + * interpreter path is truncated. + */ + if (!next_terminator(cp, buf_end)) + return -ENOEXEC; + cp = buf_end; + } + /* NUL-terminate the buffer and any trailing spaces/tabs. */ *cp = '\0'; while (cp > bprm->buf) { cp--; -- cgit v1.2.3