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Thu, 18 Mar 2021 10:52:32 +0000 Date: Thu, 18 Mar 2021 11:52:30 +0100 From: Christian Brauner To: Richard Guy Briggs Subject: Re: [PATCH 1/2] audit: add support for the openat2 syscall Message-ID: <20210318105230.4ggpg5r3clloa6br@wittgenstein> References: <49510cacfb5fbbaa312a4a389f3a6619675007ab.1616031035.git.rgb@redhat.com> <20210318104843.uiga6tmmhn5wfhbs@wittgenstein> MIME-Version: 1.0 In-Reply-To: <20210318104843.uiga6tmmhn5wfhbs@wittgenstein> X-Mimecast-Impersonation-Protect: Policy=CLT - Impersonation Protection Definition; Similar Internal Domain=false; Similar Monitored External Domain=false; Custom External Domain=false; Mimecast External Domain=false; Newly Observed Domain=false; Internal User Name=false; Custom Display Name List=false; Reply-to Address Mismatch=false; Targeted Threat Dictionary=false; Mimecast Threat Dictionary=false; Custom Threat Dictionary=false X-Scanned-By: MIMEDefang 2.78 on 10.11.54.6 X-loop: linux-audit@redhat.com X-Mailman-Approved-At: Thu, 18 Mar 2021 08:47:53 -0400 Cc: linux-s390@vger.kernel.org, linux-ia64@vger.kernel.org, linux-parisc@vger.kernel.org, x86@kernel.org, LKML , linux-fsdevel@vger.kernel.org, Aleksa Sarai , Linux-Audit Mailing List , Alexander Viro , linux-alpha@vger.kernel.org, sparclinux@vger.kernel.org, Eric Paris , linuxppc-dev@lists.ozlabs.org X-BeenThere: linux-audit@redhat.com X-Mailman-Version: 2.1.12 Precedence: junk List-Id: Linux Audit Discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-audit-bounces@redhat.com Errors-To: linux-audit-bounces@redhat.com X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=linux-audit-bounces@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Disposition: inline Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit On Thu, Mar 18, 2021 at 11:48:45AM +0100, Christian Brauner wrote: > [+Cc Aleksa, the author of openat2()] > > and a comment below. :) > > On Wed, Mar 17, 2021 at 09:47:17PM -0400, Richard Guy Briggs wrote: > > The openat2(2) syscall was added in kernel v5.6 with commit fddb5d430ad9 > > ("open: introduce openat2(2) syscall") > > > > Add the openat2(2) syscall to the audit syscall classifier. > > > > See the github issue > > https://github.com/linux-audit/audit-kernel/issues/67 > > > > Signed-off-by: Richard Guy Briggs > > --- > > arch/alpha/kernel/audit.c | 2 ++ > > arch/ia64/kernel/audit.c | 2 ++ > > arch/parisc/kernel/audit.c | 2 ++ > > arch/parisc/kernel/compat_audit.c | 2 ++ > > arch/powerpc/kernel/audit.c | 2 ++ > > arch/powerpc/kernel/compat_audit.c | 2 ++ > > arch/s390/kernel/audit.c | 2 ++ > > arch/s390/kernel/compat_audit.c | 2 ++ > > arch/sparc/kernel/audit.c | 2 ++ > > arch/sparc/kernel/compat_audit.c | 2 ++ > > arch/x86/ia32/audit.c | 2 ++ > > arch/x86/kernel/audit_64.c | 2 ++ > > kernel/auditsc.c | 3 +++ > > lib/audit.c | 4 ++++ > > lib/compat_audit.c | 4 ++++ > > 15 files changed, 35 insertions(+) > > > > diff --git a/arch/alpha/kernel/audit.c b/arch/alpha/kernel/audit.c > > index 96a9d18ff4c4..06a911b685d1 100644 > > --- a/arch/alpha/kernel/audit.c > > +++ b/arch/alpha/kernel/audit.c > > @@ -42,6 +42,8 @@ int audit_classify_syscall(int abi, unsigned syscall) > > return 3; > > case __NR_execve: > > return 5; > > + case __NR_openat2: > > + return 6; > > default: > > return 0; > > } > > diff --git a/arch/ia64/kernel/audit.c b/arch/ia64/kernel/audit.c > > index 5192ca899fe6..5eaa888c8fd3 100644 > > --- a/arch/ia64/kernel/audit.c > > +++ b/arch/ia64/kernel/audit.c > > @@ -43,6 +43,8 @@ int audit_classify_syscall(int abi, unsigned syscall) > > return 3; > > case __NR_execve: > > return 5; > > + case __NR_openat2: > > + return 6; > > default: > > return 0; > > } > > diff --git a/arch/parisc/kernel/audit.c b/arch/parisc/kernel/audit.c > > index 9eb47b2225d2..fc721a7727ba 100644 > > --- a/arch/parisc/kernel/audit.c > > +++ b/arch/parisc/kernel/audit.c > > @@ -52,6 +52,8 @@ int audit_classify_syscall(int abi, unsigned syscall) > > return 3; > > case __NR_execve: > > return 5; > > + case __NR_openat2: > > + return 6; > > default: > > return 0; > > } > > diff --git a/arch/parisc/kernel/compat_audit.c b/arch/parisc/kernel/compat_audit.c > > index 20c39c9d86a9..fc6d35918c44 100644 > > --- a/arch/parisc/kernel/compat_audit.c > > +++ b/arch/parisc/kernel/compat_audit.c > > @@ -35,6 +35,8 @@ int parisc32_classify_syscall(unsigned syscall) > > return 3; > > case __NR_execve: > > return 5; > > + case __NR_openat2: > > + return 6; > > default: > > return 1; > > } > > diff --git a/arch/powerpc/kernel/audit.c b/arch/powerpc/kernel/audit.c > > index a2dddd7f3d09..8f32700b0baa 100644 > > --- a/arch/powerpc/kernel/audit.c > > +++ b/arch/powerpc/kernel/audit.c > > @@ -54,6 +54,8 @@ int audit_classify_syscall(int abi, unsigned syscall) > > return 4; > > case __NR_execve: > > return 5; > > + case __NR_openat2: > > + return 6; > > default: > > return 0; > > } > > diff --git a/arch/powerpc/kernel/compat_audit.c b/arch/powerpc/kernel/compat_audit.c > > index 55c6ccda0a85..ebe45534b1c9 100644 > > --- a/arch/powerpc/kernel/compat_audit.c > > +++ b/arch/powerpc/kernel/compat_audit.c > > @@ -38,6 +38,8 @@ int ppc32_classify_syscall(unsigned syscall) > > return 4; > > case __NR_execve: > > return 5; > > + case __NR_openat2: > > + return 6; > > default: > > return 1; > > } > > diff --git a/arch/s390/kernel/audit.c b/arch/s390/kernel/audit.c > > index d395c6c9944c..d964cb94cfaf 100644 > > --- a/arch/s390/kernel/audit.c > > +++ b/arch/s390/kernel/audit.c > > @@ -54,6 +54,8 @@ int audit_classify_syscall(int abi, unsigned syscall) > > return 4; > > case __NR_execve: > > return 5; > > + case __NR_openat2: > > + return 6; > > default: > > return 0; > > } > > diff --git a/arch/s390/kernel/compat_audit.c b/arch/s390/kernel/compat_audit.c > > index 444fb1f66944..f7b32933ce0e 100644 > > --- a/arch/s390/kernel/compat_audit.c > > +++ b/arch/s390/kernel/compat_audit.c > > @@ -39,6 +39,8 @@ int s390_classify_syscall(unsigned syscall) > > return 4; > > case __NR_execve: > > return 5; > > + case __NR_openat2: > > + return 6; > > default: > > return 1; > > } > > diff --git a/arch/sparc/kernel/audit.c b/arch/sparc/kernel/audit.c > > index a6e91bf34d48..b6dcca9c6520 100644 > > --- a/arch/sparc/kernel/audit.c > > +++ b/arch/sparc/kernel/audit.c > > @@ -55,6 +55,8 @@ int audit_classify_syscall(int abi, unsigned int syscall) > > return 4; > > case __NR_execve: > > return 5; > > + case __NR_openat2: > > + return 6; > > default: > > return 0; > > } > > diff --git a/arch/sparc/kernel/compat_audit.c b/arch/sparc/kernel/compat_audit.c > > index 10eeb4f15b20..d2652a1083ad 100644 > > --- a/arch/sparc/kernel/compat_audit.c > > +++ b/arch/sparc/kernel/compat_audit.c > > @@ -39,6 +39,8 @@ int sparc32_classify_syscall(unsigned int syscall) > > return 4; > > case __NR_execve: > > return 5; > > + case __NR_openat2: > > + return 6; > > default: > > return 1; > > } > > diff --git a/arch/x86/ia32/audit.c b/arch/x86/ia32/audit.c > > index 6efe6cb3768a..57a02ade5503 100644 > > --- a/arch/x86/ia32/audit.c > > +++ b/arch/x86/ia32/audit.c > > @@ -39,6 +39,8 @@ int ia32_classify_syscall(unsigned syscall) > > case __NR_execve: > > case __NR_execveat: > > return 5; > > + case __NR_openat2: > > + return 6; > > default: > > return 1; > > } > > diff --git a/arch/x86/kernel/audit_64.c b/arch/x86/kernel/audit_64.c > > index 83d9cad4e68b..39de1e021258 100644 > > --- a/arch/x86/kernel/audit_64.c > > +++ b/arch/x86/kernel/audit_64.c > > @@ -53,6 +53,8 @@ int audit_classify_syscall(int abi, unsigned syscall) > > case __NR_execve: > > case __NR_execveat: > > return 5; > > + case __NR_openat2: > > + return 6; > > default: > > return 0; > > } > > diff --git a/kernel/auditsc.c b/kernel/auditsc.c > > index 8bb9ac84d2fb..f5616e70d129 100644 > > --- a/kernel/auditsc.c > > +++ b/kernel/auditsc.c > > @@ -76,6 +76,7 @@ > > #include > > #include > > #include > > +#include > > > > #include "audit.h" > > > > @@ -195,6 +196,8 @@ static int audit_match_perm(struct audit_context *ctx, int mask) > > return ((mask & AUDIT_PERM_WRITE) && ctx->argv[0] == SYS_BIND); > > case 5: /* execve */ > > return mask & AUDIT_PERM_EXEC; > > + case 6: /* openat2 */ > > + return mask & ACC_MODE((u32)((struct open_how *)ctx->argv[2])->flags); > > That looks a bit dodgy. Maybe sm like the below would be a bit better? > > diff --git a/kernel/auditsc.c b/kernel/auditsc.c > index 47fb48f42c93..531e882a5096 100644 > --- a/kernel/auditsc.c > +++ b/kernel/auditsc.c > @@ -159,6 +159,7 @@ static const struct audit_nfcfgop_tab audit_nfcfgs[] = { > > static int audit_match_perm(struct audit_context *ctx, int mask) > { > + struct open_how *openat2; > unsigned n; > if (unlikely(!ctx)) > return 0; > @@ -195,6 +196,12 @@ static int audit_match_perm(struct audit_context *ctx, int mask) > return ((mask & AUDIT_PERM_WRITE) && ctx->argv[0] == SYS_BIND); > case 5: /* execve */ > return mask & AUDIT_PERM_EXEC; > + case 6: /* openat2 */ > + openat2 = ctx->argv[2]; > + if (upper_32_bits(openat2->flags)) > + pr_warn("Some sensible warning about unknown flags"); > + > + return mask & ACC_MODE(lower_32_bits(openat2->flags)); > default: > return 0; > } > > (Ideally we'd probably notice at build-time that we've got flags > exceeding 32bits. Could probably easily been done by exposing an all > flags macro somewhere and then we can place a BUILD_BUG_ON() or sm into > such places.) And one more comment, why return a hard-coded integer from all of these architectures instead of introducing an enum in a central place with proper names idk: enum audit_match_perm_t { . . . AUDIT_MATCH_PERM_EXECVE = 5, AUDIT_MATCH_PERM_OPENAT2 = 6, . . . } Then you can drop these hard-coded comments too and it's way less brittle overall. Christian -- Linux-audit mailing list Linux-audit@redhat.com https://listman.redhat.com/mailman/listinfo/linux-audit