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https://github.com/torvalds/linux
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![]() This patchset adds execveat(2) for x86, and is derived from Meredydd Luff's patch from Sept 2012 (https://lkml.org/lkml/2012/9/11/528). The primary aim of adding an execveat syscall is to allow an implementation of fexecve(3) that does not rely on the /proc filesystem, at least for executables (rather than scripts). The current glibc version of fexecve(3) is implemented via /proc, which causes problems in sandboxed or otherwise restricted environments. Given the desire for a /proc-free fexecve() implementation, HPA suggested (https://lkml.org/lkml/2006/7/11/556) that an execveat(2) syscall would be an appropriate generalization. Also, having a new syscall means that it can take a flags argument without back-compatibility concerns. The current implementation just defines the AT_EMPTY_PATH and AT_SYMLINK_NOFOLLOW flags, but other flags could be added in future -- for example, flags for new namespaces (as suggested at https://lkml.org/lkml/2006/7/11/474). Related history: - https://lkml.org/lkml/2006/12/27/123 is an example of someone realizing that fexecve() is likely to fail in a chroot environment. - http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=514043 covered documenting the /proc requirement of fexecve(3) in its manpage, to "prevent other people from wasting their time". - https://bugzilla.redhat.com/show_bug.cgi?id=241609 described a problem where a process that did setuid() could not fexecve() because it no longer had access to /proc/self/fd; this has since been fixed. This patch (of 4): Add a new execveat(2) system call. execveat() is to execve() as openat() is to open(): it takes a file descriptor that refers to a directory, and resolves the filename relative to that. In addition, if the filename is empty and AT_EMPTY_PATH is specified, execveat() executes the file to which the file descriptor refers. This replicates the functionality of fexecve(), which is a system call in other UNIXen, but in Linux glibc it depends on opening "/proc/self/fd/<fd>" (and so relies on /proc being mounted). The filename fed to the executed program as argv[0] (or the name of the script fed to a script interpreter) will be of the form "/dev/fd/<fd>" (for an empty filename) or "/dev/fd/<fd>/<filename>", effectively reflecting how the executable was found. This does however mean that execution of a script in a /proc-less environment won't work; also, script execution via an O_CLOEXEC file descriptor fails (as the file will not be accessible after exec). Based on patches by Meredydd Luff. Signed-off-by: David Drysdale <drysdale@google.com> Cc: Meredydd Luff <meredydd@senatehouse.org> Cc: Shuah Khan <shuah.kh@samsung.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Rich Felker <dalias@aerifal.cx> Cc: Christoph Hellwig <hch@infradead.org> Cc: Michael Kerrisk <mtk.manpages@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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.. | ||
fonts | ||
lz4 | ||
lzo | ||
mpi | ||
raid6 | ||
reed_solomon | ||
xz | ||
zlib_deflate | ||
zlib_inflate | ||
.gitignore | ||
argv_split.c | ||
asn1_decoder.c | ||
assoc_array.c | ||
atomic64.c | ||
atomic64_test.c | ||
audit.c | ||
average.c | ||
bcd.c | ||
bch.c | ||
bitmap.c | ||
bitrev.c | ||
bsearch.c | ||
btree.c | ||
bug.c | ||
build_OID_registry | ||
bust_spinlocks.c | ||
check_signature.c | ||
checksum.c | ||
clz_ctz.c | ||
clz_tab.c | ||
cmdline.c | ||
compat_audit.c | ||
cordic.c | ||
cpu-notifier-error-inject.c | ||
cpu_rmap.c | ||
cpumask.c | ||
crc-ccitt.c | ||
crc-itu-t.c | ||
crc-t10dif.c | ||
crc7.c | ||
crc8.c | ||
crc16.c | ||
crc32.c | ||
crc32defs.h | ||
ctype.c | ||
debug_locks.c | ||
debugobjects.c | ||
dec_and_lock.c | ||
decompress.c | ||
decompress_bunzip2.c | ||
decompress_inflate.c | ||
decompress_unlz4.c | ||
decompress_unlzma.c | ||
decompress_unlzo.c | ||
decompress_unxz.c | ||
devres.c | ||
digsig.c | ||
div64.c | ||
dma-debug.c | ||
dump_stack.c | ||
dynamic_debug.c | ||
dynamic_queue_limits.c | ||
earlycpio.c | ||
extable.c | ||
fault-inject.c | ||
fdt.c | ||
fdt_empty_tree.c | ||
fdt_ro.c | ||
fdt_rw.c | ||
fdt_strerror.c | ||
fdt_sw.c | ||
fdt_wip.c | ||
find_last_bit.c | ||
find_next_bit.c | ||
flex_array.c | ||
flex_proportions.c | ||
gcd.c | ||
gen_crc32table.c | ||
genalloc.c | ||
glob.c | ||
halfmd4.c | ||
hexdump.c | ||
hweight.c | ||
idr.c | ||
inflate.c | ||
int_sqrt.c | ||
interval_tree.c | ||
interval_tree_test.c | ||
iomap.c | ||
iomap_copy.c | ||
iommu-helper.c | ||
ioremap.c | ||
iovec.c | ||
irq_regs.c | ||
is_single_threaded.c | ||
jedec_ddr_data.c | ||
kasprintf.c | ||
Kconfig | ||
Kconfig.debug | ||
Kconfig.kgdb | ||
Kconfig.kmemcheck | ||
kfifo.c | ||
klist.c | ||
kobject.c | ||
kobject_uevent.c | ||
kstrtox.c | ||
kstrtox.h | ||
lcm.c | ||
libcrc32c.c | ||
list_debug.c | ||
list_sort.c | ||
llist.c | ||
locking-selftest-hardirq.h | ||
locking-selftest-mutex.h | ||
locking-selftest-rlock-hardirq.h | ||
locking-selftest-rlock-softirq.h | ||
locking-selftest-rlock.h | ||
locking-selftest-rsem.h | ||
locking-selftest-softirq.h | ||
locking-selftest-spin-hardirq.h | ||
locking-selftest-spin-softirq.h | ||
locking-selftest-spin.h | ||
locking-selftest-wlock-hardirq.h | ||
locking-selftest-wlock-softirq.h | ||
locking-selftest-wlock.h | ||
locking-selftest-wsem.h | ||
locking-selftest.c | ||
lockref.c | ||
lru_cache.c | ||
Makefile | ||
md5.c | ||
memory-notifier-error-inject.c | ||
memweight.c | ||
net_utils.c | ||
nlattr.c | ||
notifier-error-inject.c | ||
notifier-error-inject.h | ||
of-reconfig-notifier-error-inject.c | ||
oid_registry.c | ||
parser.c | ||
pci_iomap.c | ||
percpu-refcount.c | ||
percpu_counter.c | ||
percpu_ida.c | ||
percpu_test.c | ||
plist.c | ||
pm-notifier-error-inject.c | ||
proportions.c | ||
radix-tree.c | ||
random32.c | ||
ratelimit.c | ||
rational.c | ||
rbtree.c | ||
rbtree_test.c | ||
reciprocal_div.c | ||
rhashtable.c | ||
scatterlist.c | ||
seq_buf.c | ||
sha1.c | ||
show_mem.c | ||
smp_processor_id.c | ||
sort.c | ||
stmp_device.c | ||
string.c | ||
string_helpers.c | ||
strncpy_from_user.c | ||
strnlen_user.c | ||
swiotlb.c | ||
syscall.c | ||
test-kstrtox.c | ||
test-string_helpers.c | ||
test_bpf.c | ||
test_firmware.c | ||
test_module.c | ||
test_user_copy.c | ||
textsearch.c | ||
timerqueue.c | ||
ts_bm.c | ||
ts_fsm.c | ||
ts_kmp.c | ||
ucs2_string.c | ||
usercopy.c | ||
uuid.c | ||
vsprintf.c |