From ba830885656414101b2f8ca88786524d4bb5e8c1 Mon Sep 17 00:00:00 2001 From: Kristina Martsenko Date: Fri, 7 Dec 2018 18:39:28 +0000 Subject: arm64: add prctl control for resetting ptrauth keys Add an arm64-specific prctl to allow a thread to reinitialize its pointer authentication keys to random values. This can be useful when exec() is not used for starting new processes, to ensure that different processes still have different keys. Signed-off-by: Kristina Martsenko Signed-off-by: Will Deacon --- kernel/sys.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'kernel/sys.c') diff --git a/kernel/sys.c b/kernel/sys.c index 123bd73046ec..64b5a230f38d 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -121,6 +121,9 @@ #ifndef SVE_GET_VL # define SVE_GET_VL() (-EINVAL) #endif +#ifndef PAC_RESET_KEYS +# define PAC_RESET_KEYS(a, b) (-EINVAL) +#endif /* * this is where the system-wide overflow UID and GID are defined, for @@ -2476,6 +2479,11 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3, return -EINVAL; error = arch_prctl_spec_ctrl_set(me, arg2, arg3); break; + case PR_PAC_RESET_KEYS: + if (arg3 || arg4 || arg5) + return -EINVAL; + error = PAC_RESET_KEYS(me, arg2); + break; default: error = -EINVAL; break; -- cgit v1.2.3 From 96d4f267e40f9509e8a66e2b39e8b95655617693 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Thu, 3 Jan 2019 18:57:57 -0800 Subject: Remove 'type' argument from access_ok() function Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument of the user address range verification function since we got rid of the old racy i386-only code to walk page tables by hand. It existed because the original 80386 would not honor the write protect bit when in kernel mode, so you had to do COW by hand before doing any user access. But we haven't supported that in a long time, and these days the 'type' argument is a purely historical artifact. A discussion about extending 'user_access_begin()' to do the range checking resulted this patch, because there is no way we're going to move the old VERIFY_xyz interface to that model. And it's best done at the end of the merge window when I've done most of my merges, so let's just get this done once and for all. This patch was mostly done with a sed-script, with manual fix-ups for the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form. There were a couple of notable cases: - csky still had the old "verify_area()" name as an alias. - the iter_iov code had magical hardcoded knowledge of the actual values of VERIFY_{READ,WRITE} (not that they mattered, since nothing really used it) - microblaze used the type argument for a debug printout but other than those oddities this should be a total no-op patch. I tried to fix up all architectures, did fairly extensive grepping for access_ok() uses, and the changes are trivial, but I may have missed something. Any missed conversion should be trivially fixable, though. Signed-off-by: Linus Torvalds --- kernel/sys.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/sys.c') diff --git a/kernel/sys.c b/kernel/sys.c index 64b5a230f38d..a48cbf1414b8 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -2627,7 +2627,7 @@ COMPAT_SYSCALL_DEFINE1(sysinfo, struct compat_sysinfo __user *, info) s.freehigh >>= bitcount; } - if (!access_ok(VERIFY_WRITE, info, sizeof(struct compat_sysinfo)) || + if (!access_ok(info, sizeof(struct compat_sysinfo)) || __put_user(s.uptime, &info->uptime) || __put_user(s.loads[0], &info->loads[0]) || __put_user(s.loads[1], &info->loads[1]) || -- cgit v1.2.3 From b7285b425318331c2de4af2a784a18e6dccef484 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Jonathan=20Neusch=C3=A4fer?= Date: Sat, 12 Jan 2019 18:14:30 +0100 Subject: kernel/sys.c: Clarify that UNAME26 does not generate unique versions anymore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit UNAME26 is a mechanism to report Linux's version as 2.6.x, for compatibility with old/broken software. Due to the way it is implemented, it would have to be updated after 5.0, to keep the resulting versions unique. Linus Torvalds argued: "Do we actually need this? I'd rather let it bitrot, and just let it return random versions. It will just start again at 2.4.60, won't it? Anybody who uses UNAME26 for a 5.x kernel might as well think it's still 4.x. The user space is so old that it can't possibly care about differences between 4.x and 5.x, can it? The only thing that matters is that it shows "2.4.", which it will do regardless" Signed-off-by: Jonathan Neuschäfer Signed-off-by: Linus Torvalds --- kernel/sys.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'kernel/sys.c') diff --git a/kernel/sys.c b/kernel/sys.c index a48cbf1414b8..f7eb62eceb24 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -1207,7 +1207,8 @@ DECLARE_RWSEM(uts_sem); /* * Work around broken programs that cannot handle "Linux 3.0". * Instead we map 3.x to 2.6.40+x, so e.g. 3.0 would be 2.6.40 - * And we map 4.x to 2.6.60+x, so 4.0 would be 2.6.60. + * And we map 4.x and later versions to 2.6.60+x, so 4.0/5.0/6.0/... would be + * 2.6.60. */ static int override_release(char __user *release, size_t len) { -- cgit v1.2.3 From 40852275a94afb3e836be9248399e036982d1a79 Mon Sep 17 00:00:00 2001 From: Micah Morton Date: Tue, 22 Jan 2019 14:42:09 -0800 Subject: LSM: add SafeSetID module that gates setid calls This change ensures that the set*uid family of syscalls in kernel/sys.c (setreuid, setuid, setresuid, setfsuid) all call ns_capable_common with the CAP_OPT_INSETID flag, so capability checks in the security_capable hook can know whether they are being called from within a set*uid syscall. This change is a no-op by itself, but is needed for the proposed SafeSetID LSM. Signed-off-by: Micah Morton Acked-by: Kees Cook Signed-off-by: James Morris --- kernel/sys.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'kernel/sys.c') diff --git a/kernel/sys.c b/kernel/sys.c index f7eb62eceb24..c5f875048aef 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -516,7 +516,7 @@ long __sys_setreuid(uid_t ruid, uid_t euid) new->uid = kruid; if (!uid_eq(old->uid, kruid) && !uid_eq(old->euid, kruid) && - !ns_capable(old->user_ns, CAP_SETUID)) + !ns_capable_setid(old->user_ns, CAP_SETUID)) goto error; } @@ -525,7 +525,7 @@ long __sys_setreuid(uid_t ruid, uid_t euid) if (!uid_eq(old->uid, keuid) && !uid_eq(old->euid, keuid) && !uid_eq(old->suid, keuid) && - !ns_capable(old->user_ns, CAP_SETUID)) + !ns_capable_setid(old->user_ns, CAP_SETUID)) goto error; } @@ -584,7 +584,7 @@ long __sys_setuid(uid_t uid) old = current_cred(); retval = -EPERM; - if (ns_capable(old->user_ns, CAP_SETUID)) { + if (ns_capable_setid(old->user_ns, CAP_SETUID)) { new->suid = new->uid = kuid; if (!uid_eq(kuid, old->uid)) { retval = set_user(new); @@ -646,7 +646,7 @@ long __sys_setresuid(uid_t ruid, uid_t euid, uid_t suid) old = current_cred(); retval = -EPERM; - if (!ns_capable(old->user_ns, CAP_SETUID)) { + if (!ns_capable_setid(old->user_ns, CAP_SETUID)) { if (ruid != (uid_t) -1 && !uid_eq(kruid, old->uid) && !uid_eq(kruid, old->euid) && !uid_eq(kruid, old->suid)) goto error; @@ -814,7 +814,7 @@ long __sys_setfsuid(uid_t uid) if (uid_eq(kuid, old->uid) || uid_eq(kuid, old->euid) || uid_eq(kuid, old->suid) || uid_eq(kuid, old->fsuid) || - ns_capable(old->user_ns, CAP_SETUID)) { + ns_capable_setid(old->user_ns, CAP_SETUID)) { if (!uid_eq(kuid, old->fsuid)) { new->fsuid = kuid; if (security_task_fix_setuid(new, old, LSM_SETID_FS) == 0) -- cgit v1.2.3 From 21f63a5da2499a1286d36986d5e02db96c350d8d Mon Sep 17 00:00:00 2001 From: Mathieu Malaterre Date: Thu, 7 Mar 2019 16:26:53 -0800 Subject: kernel/sys: annotate implicit fall through There is a plan to build the kernel with -Wimplicit-fallthrough and this place in the code produced a warning (W=1). This commit remove the following warning: kernel/sys.c:1748:6: warning: this statement may fall through [-Wimplicit-fallthrough=] Link: http://lkml.kernel.org/r/20190114203347.17530-1-malat@debian.org Signed-off-by: Mathieu Malaterre Reviewed-by: Andrew Morton Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/sys.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel/sys.c') diff --git a/kernel/sys.c b/kernel/sys.c index f7eb62eceb24..dc5d9e636d48 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -1747,6 +1747,7 @@ void getrusage(struct task_struct *p, int who, struct rusage *r) if (who == RUSAGE_CHILDREN) break; + /* fall through */ case RUSAGE_SELF: thread_group_cputime_adjusted(p, &tgutime, &tgstime); -- cgit v1.2.3