kernel/git/stable/linux.git/fs/nfsd, branch linux-4.18.y

nfsd: COPY and CLONE operations require the saved filehandle to be set

2018-11-21T08:22:09+00:00

commit 01310bb7c9c98752cc763b36532fab028e0f8f81 upstream. Make sure we have a saved filehandle, otherwise we'll oops with a null pointer dereference in nfs4_preprocess_stateid_op(). Signed-off-by: Scott Mayhew Cc: stable@vger.kernel.org Signed-off-by: J. Bruce Fields Signed-off-by: Greg Kroah-Hartman

nfsd: correctly decrement odstate refcount in error path

2018-11-13T19:12:46+00:00

commit bd8d725078867cda250fe94b9c5a067b4a64ca74 upstream. alloc_init_deleg() both allocates an nfs4_delegation, and bumps the refcount on odstate. So after this point, we need to put_clnt_odstate() and nfs4_put_stid() to not leave the odstate refcount inappropriately bumped. Signed-off-by: Andrew Elble Reviewed-by: Jeff Layton Cc: stable@vger.kernel.org Signed-off-by: J. Bruce Fields Signed-off-by: Greg Kroah-Hartman

vfs: swap names of {do,vfs}_clone_file_range()

2018-11-10T15:49:44+00:00

commit a725356b6659469d182d662f22d770d83d3bc7b5 upstream. Commit 031a072a0b8a ("vfs: call vfs_clone_file_range() under freeze protection") created a wrapper do_clone_file_range() around vfs_clone_file_range() moving the freeze protection to former, so overlayfs could call the latter. The more common vfs practice is to call do_xxx helpers from vfs_xxx helpers, where freeze protecction is taken in the vfs_xxx helper, so this anomality could be a source of confusion. It seems that commit 8ede205541ff ("ovl: add reflink/copyfile/dedup support") may have fallen a victim to this confusion - ovl_clone_file_range() calls the vfs_clone_file_range() helper in the hope of getting freeze protection on upper fs, but in fact results in overlayfs allowing to bypass upper fs freeze protection. Swap the names of the two helpers to conform to common vfs practice and call the correct helpers from overlayfs and nfsd. Signed-off-by: Amir Goldstein Signed-off-by: Miklos Szeredi Fixes: 031a072a0b8a ("vfs: call vfs_clone_file_range() under freeze...") Signed-off-by: Amir Goldstein Signed-off-by: Sasha Levin

nfsd: fix corrupted reply to badly ordered compound

2018-10-03T23:59:15+00:00

[ Upstream commit 5b7b15aee641904ae269be9846610a3950cbd64c ] We're encoding a single op in the reply but leaving the number of ops zero, so the reply makes no sense. Somewhat academic as this isn't a case any real client will hit, though in theory perhaps that could change in a future protocol extension. Reviewed-by: Jeff Layton Signed-off-by: J. Bruce Fields Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

nfsd: fix leaked file lock with nfs exported overlayfs

2018-09-09T08:32:38+00:00

commit 64bed6cbe38bc95689fb9399872d9ce250192f90 upstream. nfsd and lockd call vfs_lock_file() to lock/unlock the inode returned by locks_inode(file). Many places in nfsd/lockd code use the inode returned by file_inode(file) for lock manipulation. With Overlayfs, file_inode() (the underlying inode) is not the same object as locks_inode() (the overlay inode). This can result in "Leaked POSIX lock" messages and eventually to a kernel crash as reported by Eddie Horng: https://marc.info/?l=linux-unionfs&m=153086643202072&w=2 Fix all the call sites in nfsd/lockd that should use locks_inode(). This is a correctness bug that manifested when overlayfs gained NFS export support in v4.16. Reported-by: Eddie Horng Tested-by: Eddie Horng Cc: Jeff Layton Fixes: 8383f1748829 ("ovl: wire up NFS export operations") Cc: stable@vger.kernel.org Signed-off-by: Amir Goldstein Signed-off-by: J. Bruce Fields Signed-off-by: Greg Kroah-Hartman

Merge tag 'vfs-timespec64' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/playground

2018-06-14T22:31:07+00:00

Pull inode timestamps conversion to timespec64 from Arnd Bergmann: "This is a late set of changes from Deepa Dinamani doing an automated treewide conversion of the inode and iattr structures from 'timespec' to 'timespec64', to push the conversion from the VFS layer into the individual file systems. As Deepa writes: 'The series aims to switch vfs timestamps to use struct timespec64. Currently vfs uses struct timespec, which is not y2038 safe. The series involves the following: 1. Add vfs helper functions for supporting struct timepec64 timestamps. 2. Cast prints of vfs timestamps to avoid warnings after the switch. 3. Simplify code using vfs timestamps so that the actual replacement becomes easy. 4. Convert vfs timestamps to use struct timespec64 using a script. This is a flag day patch. Next steps: 1. Convert APIs that can handle timespec64, instead of converting timestamps at the boundaries. 2. Update internal data structures to avoid timestamp conversions' Thomas Gleixner adds: 'I think there is no point to drag that out for the next merge window. The whole thing needs to be done in one go for the core changes which means that you're going to play that catchup game forever. Let's get over with it towards the end of the merge window'" * tag 'vfs-timespec64' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/playground: pstore: Remove bogus format string definition vfs: change inode times to use struct timespec64 pstore: Convert internal records to timespec64 udf: Simplify calls to udf_disk_stamp_to_time fs: nfs: get rid of memcpys for inode times ceph: make inode time prints to be long long lustre: Use long long type to print inode time fs: add timespec64_truncate()

Merge branch 'vfs_timespec64' of https://github.com/deepa-hub/vfs into vfs-timespec64

2018-06-14T12:54:00+00:00

Pull the timespec64 conversion from Deepa Dinamani: "The series aims to switch vfs timestamps to use struct timespec64. Currently vfs uses struct timespec, which is not y2038 safe. The flag patch applies cleanly. I've not seen the timestamps update logic change often. The series applies cleanly on 4.17-rc6 and linux-next tip (top commit: next-20180517). I'm not sure how to merge this kind of a series with a flag patch. We are targeting 4.18 for this. Let me know if you have other suggestions. The series involves the following: 1. Add vfs helper functions for supporting struct timepec64 timestamps. 2. Cast prints of vfs timestamps to avoid warnings after the switch. 3. Simplify code using vfs timestamps so that the actual replacement becomes easy. 4. Convert vfs timestamps to use struct timespec64 using a script. This is a flag day patch. I've tried to keep the conversions with the script simple, to aid in the reviews. I've kept all the internal filesystem data structures and function signatures the same. Next steps: 1. Convert APIs that can handle timespec64, instead of converting timestamps at the boundaries. 2. Update internal data structures to avoid timestamp conversions." I've pulled it into a branch based on top of the NFS changes that are now in mainline, so I could resolve the non-obvious conflict between the two while merging. Signed-off-by: Arnd Bergmann

Merge tag 'overflow-v4.18-rc1-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

2018-06-13T01:28:00+00:00

Pull more overflow updates from Kees Cook: "The rest of the overflow changes for v4.18-rc1. This includes the explicit overflow fixes from Silvio, further struct_size() conversions from Matthew, and a bug fix from Dan. But the bulk of it is the treewide conversions to use either the 2-factor argument allocators (e.g. kmalloc(a * b, ...) into kmalloc_array(a, b, ...) or the array_size() macros (e.g. vmalloc(a * b) into vmalloc(array_size(a, b)). Coccinelle was fighting me on several fronts, so I've done a bunch of manual whitespace updates in the patches as well. Summary: - Error path bug fix for overflow tests (Dan) - Additional struct_size() conversions (Matthew, Kees) - Explicitly reported overflow fixes (Silvio, Kees) - Add missing kvcalloc() function (Kees) - Treewide conversions of allocators to use either 2-factor argument variant when available, or array_size() and array3_size() as needed (Kees)" * tag 'overflow-v4.18-rc1-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux: (26 commits) treewide: Use array_size in f2fs_kvzalloc() treewide: Use array_size() in f2fs_kzalloc() treewide: Use array_size() in f2fs_kmalloc() treewide: Use array_size() in sock_kmalloc() treewide: Use array_size() in kvzalloc_node() treewide: Use array_size() in vzalloc_node() treewide: Use array_size() in vzalloc() treewide: Use array_size() in vmalloc() treewide: devm_kzalloc() -> devm_kcalloc() treewide: devm_kmalloc() -> devm_kmalloc_array() treewide: kvzalloc() -> kvcalloc() treewide: kvmalloc() -> kvmalloc_array() treewide: kzalloc_node() -> kcalloc_node() treewide: kzalloc() -> kcalloc() treewide: kmalloc() -> kmalloc_array() mm: Introduce kvcalloc() video: uvesafb: Fix integer overflow in allocation UBIFS: Fix potential integer overflow in allocation leds: Use struct_size() in allocation Convert intel uncore to struct_size ...

treewide: Use array_size() in vzalloc()

2018-06-12T23:19:22+00:00

The vzalloc() function has no 2-factor argument form, so multiplication factors need to be wrapped in array_size(). This patch replaces cases of: vzalloc(a * b) with: vzalloc(array_size(a, b)) as well as handling cases of: vzalloc(a * b * c) with: vzalloc(array3_size(a, b, c)) This does, however, attempt to ignore constant size factors like: vzalloc(4 * 1024) though any constants defined via macros get caught up in the conversion. Any factors with a sizeof() of "unsigned char", "char", and "u8" were dropped, since they're redundant. The Coccinelle script used for this was: // Fix redundant parens around sizeof(). @@ type TYPE; expression THING, E; @@ ( vzalloc( - (sizeof(TYPE)) * E + sizeof(TYPE) * E , ...) | vzalloc( - (sizeof(THING)) * E + sizeof(THING) * E , ...) ) // Drop single-byte sizes and redundant parens. @@ expression COUNT; typedef u8; typedef __u8; @@ ( vzalloc( - sizeof(u8) * (COUNT) + COUNT , ...) | vzalloc( - sizeof(__u8) * (COUNT) + COUNT , ...) | vzalloc( - sizeof(char) * (COUNT) + COUNT , ...) | vzalloc( - sizeof(unsigned char) * (COUNT) + COUNT , ...) | vzalloc( - sizeof(u8) * COUNT + COUNT , ...) | vzalloc( - sizeof(__u8) * COUNT + COUNT , ...) | vzalloc( - sizeof(char) * COUNT + COUNT , ...) | vzalloc( - sizeof(unsigned char) * COUNT + COUNT , ...) ) // 2-factor product with sizeof(type/expression) and identifier or constant. @@ type TYPE; expression THING; identifier COUNT_ID; constant COUNT_CONST; @@ ( vzalloc( - sizeof(TYPE) * (COUNT_ID) + array_size(COUNT_ID, sizeof(TYPE)) , ...) | vzalloc( - sizeof(TYPE) * COUNT_ID + array_size(COUNT_ID, sizeof(TYPE)) , ...) | vzalloc( - sizeof(TYPE) * (COUNT_CONST) + array_size(COUNT_CONST, sizeof(TYPE)) , ...) | vzalloc( - sizeof(TYPE) * COUNT_CONST + array_size(COUNT_CONST, sizeof(TYPE)) , ...) | vzalloc( - sizeof(THING) * (COUNT_ID) + array_size(COUNT_ID, sizeof(THING)) , ...) | vzalloc( - sizeof(THING) * COUNT_ID + array_size(COUNT_ID, sizeof(THING)) , ...) | vzalloc( - sizeof(THING) * (COUNT_CONST) + array_size(COUNT_CONST, sizeof(THING)) , ...) | vzalloc( - sizeof(THING) * COUNT_CONST + array_size(COUNT_CONST, sizeof(THING)) , ...) ) // 2-factor product, only identifiers. @@ identifier SIZE, COUNT; @@ vzalloc( - SIZE * COUNT + array_size(COUNT, SIZE) , ...) // 3-factor product with 1 sizeof(type) or sizeof(expression), with // redundant parens removed. @@ expression THING; identifier STRIDE, COUNT; type TYPE; @@ ( vzalloc( - sizeof(TYPE) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | vzalloc( - sizeof(TYPE) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | vzalloc( - sizeof(TYPE) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | vzalloc( - sizeof(TYPE) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | vzalloc( - sizeof(THING) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | vzalloc( - sizeof(THING) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | vzalloc( - sizeof(THING) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | vzalloc( - sizeof(THING) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) ) // 3-factor product with 2 sizeof(variable), with redundant parens removed. @@ expression THING1, THING2; identifier COUNT; type TYPE1, TYPE2; @@ ( vzalloc( - sizeof(TYPE1) * sizeof(TYPE2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | vzalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | vzalloc( - sizeof(THING1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | vzalloc( - sizeof(THING1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | vzalloc( - sizeof(TYPE1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) | vzalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) ) // 3-factor product, only identifiers, with redundant parens removed. @@ identifier STRIDE, SIZE, COUNT; @@ ( vzalloc( - (COUNT) * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | vzalloc( - COUNT * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | vzalloc( - COUNT * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | vzalloc( - (COUNT) * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | vzalloc( - COUNT * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | vzalloc( - (COUNT) * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | vzalloc( - (COUNT) * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | vzalloc( - COUNT * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) ) // Any remaining multi-factor products, first at least 3-factor products // when they're not all constants... @@ expression E1, E2, E3; constant C1, C2, C3; @@ ( vzalloc(C1 * C2 * C3, ...) | vzalloc( - E1 * E2 * E3 + array3_size(E1, E2, E3) , ...) ) // And then all remaining 2 factors products when they're not all constants. @@ expression E1, E2; constant C1, C2; @@ ( vzalloc(C1 * C2, ...) | vzalloc( - E1 * E2 + array_size(E1, E2) , ...) ) Signed-off-by: Kees Cook

treewide: kzalloc() -> kcalloc()

2018-06-12T23:19:22+00:00

The kzalloc() function has a 2-factor argument form, kcalloc(). This patch replaces cases of: kzalloc(a * b, gfp) with: kcalloc(a * b, gfp) as well as handling cases of: kzalloc(a * b * c, gfp) with: kzalloc(array3_size(a, b, c), gfp) as it's slightly less ugly than: kzalloc_array(array_size(a, b), c, gfp) This does, however, attempt to ignore constant size factors like: kzalloc(4 * 1024, gfp) though any constants defined via macros get caught up in the conversion. Any factors with a sizeof() of "unsigned char", "char", and "u8" were dropped, since they're redundant. The Coccinelle script used for this was: // Fix redundant parens around sizeof(). @@ type TYPE; expression THING, E; @@ ( kzalloc( - (sizeof(TYPE)) * E + sizeof(TYPE) * E , ...) | kzalloc( - (sizeof(THING)) * E + sizeof(THING) * E , ...) ) // Drop single-byte sizes and redundant parens. @@ expression COUNT; typedef u8; typedef __u8; @@ ( kzalloc( - sizeof(u8) * (COUNT) + COUNT , ...) | kzalloc( - sizeof(__u8) * (COUNT) + COUNT , ...) | kzalloc( - sizeof(char) * (COUNT) + COUNT , ...) | kzalloc( - sizeof(unsigned char) * (COUNT) + COUNT , ...) | kzalloc( - sizeof(u8) * COUNT + COUNT , ...) | kzalloc( - sizeof(__u8) * COUNT + COUNT , ...) | kzalloc( - sizeof(char) * COUNT + COUNT , ...) | kzalloc( - sizeof(unsigned char) * COUNT + COUNT , ...) ) // 2-factor product with sizeof(type/expression) and identifier or constant. @@ type TYPE; expression THING; identifier COUNT_ID; constant COUNT_CONST; @@ ( - kzalloc + kcalloc ( - sizeof(TYPE) * (COUNT_ID) + COUNT_ID, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(TYPE) * COUNT_ID + COUNT_ID, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(TYPE) * (COUNT_CONST) + COUNT_CONST, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(TYPE) * COUNT_CONST + COUNT_CONST, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * (COUNT_ID) + COUNT_ID, sizeof(THING) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * COUNT_ID + COUNT_ID, sizeof(THING) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * (COUNT_CONST) + COUNT_CONST, sizeof(THING) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * COUNT_CONST + COUNT_CONST, sizeof(THING) , ...) ) // 2-factor product, only identifiers. @@ identifier SIZE, COUNT; @@ - kzalloc + kcalloc ( - SIZE * COUNT + COUNT, SIZE , ...) // 3-factor product with 1 sizeof(type) or sizeof(expression), with // redundant parens removed. @@ expression THING; identifier STRIDE, COUNT; type TYPE; @@ ( kzalloc( - sizeof(TYPE) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kzalloc( - sizeof(TYPE) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kzalloc( - sizeof(TYPE) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kzalloc( - sizeof(TYPE) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kzalloc( - sizeof(THING) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kzalloc( - sizeof(THING) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kzalloc( - sizeof(THING) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kzalloc( - sizeof(THING) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) ) // 3-factor product with 2 sizeof(variable), with redundant parens removed. @@ expression THING1, THING2; identifier COUNT; type TYPE1, TYPE2; @@ ( kzalloc( - sizeof(TYPE1) * sizeof(TYPE2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | kzalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | kzalloc( - sizeof(THING1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | kzalloc( - sizeof(THING1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | kzalloc( - sizeof(TYPE1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) | kzalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) ) // 3-factor product, only identifiers, with redundant parens removed. @@ identifier STRIDE, SIZE, COUNT; @@ ( kzalloc( - (COUNT) * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - COUNT * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - COUNT * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - (COUNT) * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - COUNT * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - (COUNT) * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - (COUNT) * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - COUNT * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) ) // Any remaining multi-factor products, first at least 3-factor products, // when they're not all constants... @@ expression E1, E2, E3; constant C1, C2, C3; @@ ( kzalloc(C1 * C2 * C3, ...) | kzalloc( - (E1) * E2 * E3 + array3_size(E1, E2, E3) , ...) | kzalloc( - (E1) * (E2) * E3 + array3_size(E1, E2, E3) , ...) | kzalloc( - (E1) * (E2) * (E3) + array3_size(E1, E2, E3) , ...) | kzalloc( - E1 * E2 * E3 + array3_size(E1, E2, E3) , ...) ) // And then all remaining 2 factors products when they're not all constants, // keeping sizeof() as the second factor argument. @@ expression THING, E1, E2; type TYPE; constant C1, C2, C3; @@ ( kzalloc(sizeof(THING) * C2, ...) | kzalloc(sizeof(TYPE) * C2, ...) | kzalloc(C1 * C2 * C3, ...) | kzalloc(C1 * C2, ...) | - kzalloc + kcalloc ( - sizeof(TYPE) * (E2) + E2, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(TYPE) * E2 + E2, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * (E2) + E2, sizeof(THING) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * E2 + E2, sizeof(THING) , ...) | - kzalloc + kcalloc ( - (E1) * E2 + E1, E2 , ...) | - kzalloc + kcalloc ( - (E1) * (E2) + E1, E2 , ...) | - kzalloc + kcalloc ( - E1 * E2 + E1, E2 , ...) ) Signed-off-by: Kees Cook