From 2e0a547164b1384a87fd3500a01297222b0971b0 Mon Sep 17 00:00:00 2001 From: Richard Guy Briggs Date: Fri, 3 Feb 2023 16:35:14 -0500 Subject: fanotify: Ensure consistent variable type for response The user space API for the response variable is __u32. This patch makes sure that the whole path through the kernel uses u32 so that there is no sign extension or truncation of the user space response. Suggested-by: Steve Grubb Link: https://lore.kernel.org/r/12617626.uLZWGnKmhe@x2 Signed-off-by: Richard Guy Briggs Acked-by: Paul Moore Tested-by: Steve Grubb Acked-by: Steve Grubb Signed-off-by: Jan Kara Message-Id: <3778cb0b3501bc4e686ba7770b20eb9ab0506cf4.1675373475.git.rgb@redhat.com> --- include/linux/audit.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'include') diff --git a/include/linux/audit.h b/include/linux/audit.h index 3608992848d3..d6b7d0c7ce43 100644 --- a/include/linux/audit.h +++ b/include/linux/audit.h @@ -416,7 +416,7 @@ extern void __audit_log_capset(const struct cred *new, const struct cred *old); extern void __audit_mmap_fd(int fd, int flags); extern void __audit_openat2_how(struct open_how *how); extern void __audit_log_kern_module(char *name); -extern void __audit_fanotify(unsigned int response); +extern void __audit_fanotify(u32 response); extern void __audit_tk_injoffset(struct timespec64 offset); extern void __audit_ntp_log(const struct audit_ntp_data *ad); extern void __audit_log_nfcfg(const char *name, u8 af, unsigned int nentries, @@ -523,7 +523,7 @@ static inline void audit_log_kern_module(char *name) __audit_log_kern_module(name); } -static inline void audit_fanotify(unsigned int response) +static inline void audit_fanotify(u32 response) { if (!audit_dummy_context()) __audit_fanotify(response); @@ -679,7 +679,7 @@ static inline void audit_log_kern_module(char *name) { } -static inline void audit_fanotify(unsigned int response) +static inline void audit_fanotify(u32 response) { } static inline void audit_tk_injoffset(struct timespec64 offset) -- cgit From 70529a199574c15a40f46b14256633b02ba10ca2 Mon Sep 17 00:00:00 2001 From: Richard Guy Briggs Date: Fri, 3 Feb 2023 16:35:15 -0500 Subject: fanotify: define struct members to hold response decision context This patch adds a flag, FAN_INFO and an extensible buffer to provide additional information about response decisions. The buffer contains one or more headers defining the information type and the length of the following information. The patch defines one additional information type, FAN_RESPONSE_INFO_AUDIT_RULE, to audit a rule number. This will allow for the creation of other information types in the future if other users of the API identify different needs. The kernel can be tested if it supports a given info type by supplying the complete info extension but setting fd to FAN_NOFD. It will return the expected size but not issue an audit record. Suggested-by: Steve Grubb Link: https://lore.kernel.org/r/2745105.e9J7NaK4W3@x2 Suggested-by: Jan Kara Link: https://lore.kernel.org/r/20201001101219.GE17860@quack2.suse.cz Tested-by: Steve Grubb Acked-by: Steve Grubb Signed-off-by: Richard Guy Briggs Signed-off-by: Jan Kara Message-Id: <10177cfcae5480926b7176321a28d9da6835b667.1675373475.git.rgb@redhat.com> --- include/linux/fanotify.h | 5 +++++ include/uapi/linux/fanotify.h | 30 +++++++++++++++++++++++++++++- 2 files changed, 34 insertions(+), 1 deletion(-) (limited to 'include') diff --git a/include/linux/fanotify.h b/include/linux/fanotify.h index 8ad743def6f3..4f1c4f603118 100644 --- a/include/linux/fanotify.h +++ b/include/linux/fanotify.h @@ -122,6 +122,11 @@ #define ALL_FANOTIFY_EVENT_BITS (FANOTIFY_OUTGOING_EVENTS | \ FANOTIFY_EVENT_FLAGS) +/* These masks check for invalid bits in permission responses. */ +#define FANOTIFY_RESPONSE_ACCESS (FAN_ALLOW | FAN_DENY) +#define FANOTIFY_RESPONSE_FLAGS (FAN_AUDIT | FAN_INFO) +#define FANOTIFY_RESPONSE_VALID_MASK (FANOTIFY_RESPONSE_ACCESS | FANOTIFY_RESPONSE_FLAGS) + /* Do not use these old uapi constants internally */ #undef FAN_ALL_CLASS_BITS #undef FAN_ALL_INIT_FLAGS diff --git a/include/uapi/linux/fanotify.h b/include/uapi/linux/fanotify.h index 436258214bb0..cd14c94e9a1e 100644 --- a/include/uapi/linux/fanotify.h +++ b/include/uapi/linux/fanotify.h @@ -188,15 +188,43 @@ struct fanotify_event_info_error { __u32 error_count; }; +/* + * User space may need to record additional information about its decision. + * The extra information type records what kind of information is included. + * The default is none. We also define an extra information buffer whose + * size is determined by the extra information type. + * + * If the information type is Audit Rule, then the information following + * is the rule number that triggered the user space decision that + * requires auditing. + */ + +#define FAN_RESPONSE_INFO_NONE 0 +#define FAN_RESPONSE_INFO_AUDIT_RULE 1 + struct fanotify_response { __s32 fd; __u32 response; }; +struct fanotify_response_info_header { + __u8 type; + __u8 pad; + __u16 len; +}; + +struct fanotify_response_info_audit_rule { + struct fanotify_response_info_header hdr; + __u32 rule_number; + __u32 subj_trust; + __u32 obj_trust; +}; + /* Legit userspace responses to a _PERM event */ #define FAN_ALLOW 0x01 #define FAN_DENY 0x02 -#define FAN_AUDIT 0x10 /* Bit mask to create audit record for result */ +#define FAN_AUDIT 0x10 /* Bitmask to create audit record for result */ +#define FAN_INFO 0x20 /* Bitmask to indicate additional information */ /* No fd set in event */ #define FAN_NOFD -1 -- cgit From 032bffd494e3924cc8b854b696ef9b5b7396b883 Mon Sep 17 00:00:00 2001 From: Richard Guy Briggs Date: Fri, 3 Feb 2023 16:35:16 -0500 Subject: fanotify,audit: Allow audit to use the full permission event response This patch passes the full response so that the audit function can use all of it. The audit function was updated to log the additional information in the AUDIT_FANOTIFY record. Currently the only type of fanotify info that is defined is an audit rule number, but convert it to hex encoding to future-proof the field. Hex encoding suggested by Paul Moore . The {subj,obj}_trust values are {0,1,2}, corresponding to no, yes, unknown. Sample records: type=FANOTIFY msg=audit(1600385147.372:590): resp=2 fan_type=1 fan_info=3137 subj_trust=3 obj_trust=5 type=FANOTIFY msg=audit(1659730979.839:284): resp=1 fan_type=0 fan_info=0 subj_trust=2 obj_trust=2 Suggested-by: Steve Grubb Link: https://lore.kernel.org/r/3075502.aeNJFYEL58@x2 Tested-by: Steve Grubb Acked-by: Steve Grubb Signed-off-by: Richard Guy Briggs Signed-off-by: Jan Kara Message-Id: --- include/linux/audit.h | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) (limited to 'include') diff --git a/include/linux/audit.h b/include/linux/audit.h index d6b7d0c7ce43..31086a72e32a 100644 --- a/include/linux/audit.h +++ b/include/linux/audit.h @@ -14,6 +14,7 @@ #include #include #include +#include #define AUDIT_INO_UNSET ((unsigned long)-1) #define AUDIT_DEV_UNSET ((dev_t)-1) @@ -416,7 +417,7 @@ extern void __audit_log_capset(const struct cred *new, const struct cred *old); extern void __audit_mmap_fd(int fd, int flags); extern void __audit_openat2_how(struct open_how *how); extern void __audit_log_kern_module(char *name); -extern void __audit_fanotify(u32 response); +extern void __audit_fanotify(u32 response, struct fanotify_response_info_audit_rule *friar); extern void __audit_tk_injoffset(struct timespec64 offset); extern void __audit_ntp_log(const struct audit_ntp_data *ad); extern void __audit_log_nfcfg(const char *name, u8 af, unsigned int nentries, @@ -523,10 +524,10 @@ static inline void audit_log_kern_module(char *name) __audit_log_kern_module(name); } -static inline void audit_fanotify(u32 response) +static inline void audit_fanotify(u32 response, struct fanotify_response_info_audit_rule *friar) { if (!audit_dummy_context()) - __audit_fanotify(response); + __audit_fanotify(response, friar); } static inline void audit_tk_injoffset(struct timespec64 offset) @@ -679,7 +680,7 @@ static inline void audit_log_kern_module(char *name) { } -static inline void audit_fanotify(u32 response) +static inline void audit_fanotify(u32 response, struct fanotify_response_info_audit_rule *friar) { } static inline void audit_tk_injoffset(struct timespec64 offset) -- cgit