Messages in this thread | | | Date | Thu, 9 Apr 2020 17:50:56 -0400 | From | Richard Guy Briggs <> | Subject | Re: [PATCH ghak96] audit: set cwd in audit context for file-related LSM audit records |
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On 2020-04-02 12:31, Vladis Dronov wrote: > Hello, Casey, all, > > ----- Original Message ----- > > From: "Casey Schaufler" <casey@schaufler-ca.com> > > Subject: Re: [PATCH ghak96] audit: set cwd in audit context for file-related LSM audit records > > > > On 4/2/2020 7:13 AM, Vladis Dronov wrote: > > > Set a current working directory in an audit context for the following > > > record > > > types in dump_common_audit_data(): LSM_AUDIT_DATA_PATH, > > > LSM_AUDIT_DATA_FILE, > > > LSM_AUDIT_DATA_IOCTL_OP, LSM_AUDIT_DATA_DENTRY, LSM_AUDIT_DATA_INODE so a > > > separate CWD record is emitted later. > > > > > > Link: https://github.com/linux-audit/audit-kernel/issues/96 > > > > I don't have a problem with the patch, but it sure would be nice > > if you explained why these events "could use a CWD record". > > (adding Richard Guy Briggs <rgb@redhat.com> which I should have been done earlier) > > I would agree, adding "cwd=" field in the LSM record itself is simpler to me.
We already have a CWD record to record this information. It usually accompanies an AUDIT_PATH record, but the intent is that it accompanies any event that has filesystem pathnames in path= or name= fields in records to help understand the command's context relative to the filesystem.
> Unfortunately, all I can say for now is "The intent was a separate CWD record, > that is already defined" requirement from the ghak#96 issue. > > Richard, could you, please, clarify since you've posted this requirement in > the ghak#96's description? > > > > Signed-off-by: Vladis Dronov <vdronov@redhat.com> > > > --- > > > out-of-commit-message-note: > > > > > > Hello, > > > Honestly, I'm not sure about "if (!context->in_syscall)" check in > > > __audit_getcwd(). It was copied from __audit_getname() and I do > > > not quite understand why it is there and if __audit_getcwd() needs > > > it. If you have an idea on this, could you please, tell? > > > > > > include/linux/audit.h | 9 ++++++++- > > > kernel/auditsc.c | 17 +++++++++++++++++ > > > security/lsm_audit.c | 5 +++++ > > > 3 files changed, 30 insertions(+), 1 deletion(-) > > > > > > diff --git a/include/linux/audit.h b/include/linux/audit.h > > > index f9ceae57ca8d..b4306abc5891 100644 > > > --- a/include/linux/audit.h > > > +++ b/include/linux/audit.h > > > @@ -268,7 +268,7 @@ extern void __audit_syscall_entry(int major, unsigned > > > long a0, unsigned long a1, > > > extern void __audit_syscall_exit(int ret_success, long ret_value); > > > extern struct filename *__audit_reusename(const __user char *uptr); > > > extern void __audit_getname(struct filename *name); > > > - > > > +extern void __audit_getcwd(void); > > > extern void __audit_inode(struct filename *name, const struct dentry > > > *dentry, > > > unsigned int flags); > > > extern void __audit_file(const struct file *); > > > @@ -327,6 +327,11 @@ static inline void audit_getname(struct filename > > > *name) > > > if (unlikely(!audit_dummy_context())) > > > __audit_getname(name); > > > } > > > +static inline void audit_getcwd(void) > > > +{ > > > + if (unlikely(!audit_dummy_context())) > > > + __audit_getcwd(); > > > +} > > > static inline void audit_inode(struct filename *name, > > > const struct dentry *dentry, > > > unsigned int aflags) { > > > @@ -545,6 +550,8 @@ static inline struct filename *audit_reusename(const > > > __user char *name) > > > } > > > static inline void audit_getname(struct filename *name) > > > { } > > > +static inline void audit_getcwd(void) > > > +{ } > > > static inline void __audit_inode(struct filename *name, > > > const struct dentry *dentry, > > > unsigned int flags) > > > diff --git a/kernel/auditsc.c b/kernel/auditsc.c > > > index 814406a35db1..16316032ef9f 100644 > > > --- a/kernel/auditsc.c > > > +++ b/kernel/auditsc.c > > > @@ -1890,6 +1890,23 @@ void __audit_getname(struct filename *name) > > > get_fs_pwd(current->fs, &context->pwd); > > > } > > > > > > +/** > > > + * __audit_getcwd - set a current working directory > > > + * > > > + * Set a current working directory of an audited process for this context. > > > + * Called from security/lsm_audit.c:dump_common_audit_data(). > > > + */ > > > +void __audit_getcwd(void) > > > +{ > > > + struct audit_context *context = audit_context(); > > > + > > > + if (!context->in_syscall) > > > + return; > > > + > > > + if (!context->pwd.dentry) > > > + get_fs_pwd(current->fs, &context->pwd); > > > +} > > > + > > > static inline int audit_copy_fcaps(struct audit_names *name, > > > const struct dentry *dentry) > > > { > > > diff --git a/security/lsm_audit.c b/security/lsm_audit.c > > > index 2d2bf49016f4..7c555621c2bd 100644 > > > --- a/security/lsm_audit.c > > > +++ b/security/lsm_audit.c > > > @@ -241,6 +241,7 @@ static void dump_common_audit_data(struct audit_buffer > > > *ab, > > > audit_log_untrustedstring(ab, inode->i_sb->s_id); > > > audit_log_format(ab, " ino=%lu", inode->i_ino); > > > } > > > + audit_getcwd(); > > > break; > > > } > > > case LSM_AUDIT_DATA_FILE: { > > > @@ -254,6 +255,7 @@ static void dump_common_audit_data(struct audit_buffer > > > *ab, > > > audit_log_untrustedstring(ab, inode->i_sb->s_id); > > > audit_log_format(ab, " ino=%lu", inode->i_ino); > > > } > > > + audit_getcwd(); > > > break; > > > } > > > case LSM_AUDIT_DATA_IOCTL_OP: { > > > @@ -269,6 +271,7 @@ static void dump_common_audit_data(struct audit_buffer > > > *ab, > > > } > > > > > > audit_log_format(ab, " ioctlcmd=0x%hx", a->u.op->cmd); > > > + audit_getcwd(); > > > break; > > > } > > > case LSM_AUDIT_DATA_DENTRY: { > > > @@ -283,6 +286,7 @@ static void dump_common_audit_data(struct audit_buffer > > > *ab, > > > audit_log_untrustedstring(ab, inode->i_sb->s_id); > > > audit_log_format(ab, " ino=%lu", inode->i_ino); > > > } > > > + audit_getcwd(); > > > break; > > > } > > > case LSM_AUDIT_DATA_INODE: { > > > @@ -300,6 +304,7 @@ static void dump_common_audit_data(struct audit_buffer > > > *ab, > > > audit_log_format(ab, " dev="); > > > audit_log_untrustedstring(ab, inode->i_sb->s_id); > > > audit_log_format(ab, " ino=%lu", inode->i_ino); > > > + audit_getcwd(); > > > break; > > > } > > > case LSM_AUDIT_DATA_TASK: { > > Best regards, > Vladis Dronov | Red Hat, Inc. | The Core Kernel | Senior Software Engineer
- RGB
-- Richard Guy Briggs <rgb@redhat.com> Sr. S/W Engineer, Kernel Security, Base Operating Systems Remote, Ottawa, Red Hat Canada IRC: rgb, SunRaycer Voice: +1.647.777.2635, Internal: (81) 32635
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