> From: Deven Bowers [mailto:deven.desai@xxxxxxxxxxxxxxxxxxx] > Sent: Tuesday, October 26, 2021 9:04 PM > On 10/25/2021 5:22 AM, Roberto Sassu wrote: > >> From:deven.desai@xxxxxxxxxxxxxxxxxxx > >> [mailto:deven.desai@xxxxxxxxxxxxxxxxxxx] > >> From: Deven Bowers<deven.desai@xxxxxxxxxxxxxxxxxxx> > >> > >> IPE's initial goal is to control both execution and the loading of > >> kernel modules based on the system's definition of trust. It > >> accomplishes this by plugging into the security hooks for execve, > >> mprotect, mmap, kernel_load_data and kernel_read_data. > >> > >> Signed-off-by: Deven Bowers<deven.desai@xxxxxxxxxxxxxxxxxxx> > >> --- > >> > >> Relevant changes since v6: > >> * Split up patch 02/12 into four parts: > >> 1. context creation [01/16] > >> 2. audit [07/16] > >> 3. evaluation loop [03/16] > >> 4. access control hooks [05/16] (this patch) > >> > >> --- > >> security/ipe/hooks.c | 149 > ++++++++++++++++++++++++++++++++++++++++++ > >> security/ipe/hooks.h | 23 ++++++- > >> security/ipe/ipe.c | 5 ++ > >> security/ipe/policy.c | 23 +++++++ > >> security/ipe/policy.h | 12 +++- > >> 5 files changed, 209 insertions(+), 3 deletions(-) > >> > >> diff --git a/security/ipe/hooks.c b/security/ipe/hooks.c > >> index ed0c886eaa5a..216242408a80 100644 > >> --- a/security/ipe/hooks.c > >> +++ b/security/ipe/hooks.c > >> @@ -6,11 +6,15 @@ > >> #include "ipe.h" > >> #include "ctx.h" > >> #include "hooks.h" > >> +#include "eval.h" > >> > >> +#include <linux/fs.h> > >> #include <linux/sched.h> > >> #include <linux/types.h> > >> #include <linux/refcount.h> > >> #include <linux/rcupdate.h> > >> +#include <linux/binfmts.h> > >> +#include <linux/mman.h> > >> > >> /** > >> * ipe_task_alloc: Assign a new context for an associated task structure. > >> @@ -56,3 +60,148 @@ void ipe_task_free(struct task_struct *task) > >> ipe_put_ctx(ctx); > >> rcu_read_unlock(); > >> } > >> + > >> +/** > >> + * ipe_on_exec: LSM hook called when a process is loaded through the exec > >> + * family of system calls. > >> + * @bprm: Supplies a pointer to a linux_binprm structure to source the file > >> + * being evaluated. > >> + * > >> + * Return: > >> + * 0 - OK > >> + * !0 - Error > >> + */ > >> +int ipe_on_exec(struct linux_binprm *bprm) > >> +{ > >> + return ipe_process_event(bprm->file, ipe_operation_exec, > >> ipe_hook_exec); > >> +} > >> + > >> +/** > >> + * ipe_on_mmap: LSM hook called when a file is loaded through the mmap > >> + * family of system calls. > >> + * @f: File being mmap'd. Can be NULL in the case of anonymous memory. > >> + * @reqprot: The requested protection on the mmap, passed from > usermode. > >> + * @prot: The effective protection on the mmap, resolved from reqprot and > >> + * system configuration. > >> + * @flags: Unused. > >> + * > >> + * Return: > >> + * 0 - OK > >> + * !0 - Error > >> + */ > >> +int ipe_on_mmap(struct file *f, unsigned long reqprot, unsigned long prot, > >> + unsigned long flags) > >> +{ > >> + if (prot & PROT_EXEC || reqprot & PROT_EXEC) > >> + return ipe_process_event(f, ipe_operation_exec, > >> ipe_hook_mmap); > >> + > >> + return 0; > >> +} > >> + > >> +/** > >> + * ipe_on_mprotect: LSM hook called when a mmap'd region of memory is > >> changing > >> + * its protections via mprotect. > >> + * @vma: Existing virtual memory area created by mmap or similar > >> + * @reqprot: The requested protection on the mmap, passed from > usermode. > >> + * @prot: The effective protection on the mmap, resolved from reqprot and > >> + * system configuration. > >> + * > >> + * Return: > >> + * 0 - OK > >> + * !0 - Error > >> + */ > >> +int ipe_on_mprotect(struct vm_area_struct *vma, unsigned long reqprot, > >> + unsigned long prot) > >> +{ > >> + /* Already Executable */ > >> + if (vma->vm_flags & VM_EXEC) > >> + return 0; > >> + > >> + if (((prot & PROT_EXEC) || reqprot & PROT_EXEC)) > >> + return ipe_process_event(vma->vm_file, ipe_operation_exec, > >> + ipe_hook_mprotect); > >> + > >> + return 0; > >> +} > >> + > >> +/** > >> + * ipe_on_kernel_read: LSM hook called when a file is being read in from > >> + * disk. > >> + * @file: Supplies a pointer to the file structure being read in from disk > >> + * @id: Supplies the enumeration identifying the purpose of the read. > >> + * @contents: Unused. > >> + * > >> + * Return: > >> + * 0 - OK > >> + * !0 - Error > >> + */ > >> +int ipe_on_kernel_read(struct file *file, enum kernel_read_file_id id, > >> + bool contents) > >> +{ > >> + enum ipe_operation op; > >> + > >> + switch (id) { > >> + case READING_FIRMWARE: > >> + op = ipe_operation_firmware; > >> + break; > >> + case READING_MODULE: > >> + op = ipe_operation_kernel_module; > >> + break; > >> + case READING_KEXEC_INITRAMFS: > >> + op = ipe_operation_kexec_initramfs; > >> + break; > >> + case READING_KEXEC_IMAGE: > >> + op = ipe_operation_kexec_image; > >> + break; > >> + case READING_POLICY: > >> + op = ipe_operation_ima_policy; > >> + break; > >> + case READING_X509_CERTIFICATE: > >> + op = ipe_operation_ima_x509; > >> + break; > >> + default: > >> + op = ipe_operation_max; > > Possible problem here. If someone (like me) adds a new file type > > and forgets to add a case, there will be an out of bound access > > in evaluate(): > > > > rules = &pol->parsed->rules[ctx->op]; > > > > due to the static definition of the rules array in the ipe_parsed_policy > > structure (array length: ipe_operation_max). > > Yeah, that's a problem. I can fix this down in the eval loop by matching > the global default and emitting a WARN here. Ok, will do a test with your new version of the patch set. Thanks Roberto HUAWEI TECHNOLOGIES Duesseldorf GmbH, HRB 56063 Managing Director: Li Peng, Zhong Ronghua > > Roberto > > > > HUAWEI TECHNOLOGIES Duesseldorf GmbH, HRB 56063 > > Managing Director: Li Peng, Zhong Ronghua > > > >> + } > >> + > >> + return ipe_process_event(file, op, ipe_hook_kernel_read); > >> +} > >> + > >> +/** > >> + * ipe_on_kernel_load_data: LSM hook called when a buffer is being read in > >> from > >> + * disk. > >> + * @id: Supplies the enumeration identifying the purpose of the read. > >> + * @contents: Unused. > >> + * > >> + * Return: > >> + * 0 - OK > >> + * !0 - Error > >> + */ > >> +int ipe_on_kernel_load_data(enum kernel_load_data_id id, bool contents) > >> +{ > >> + enum ipe_operation op; > >> + > >> + switch (id) { > >> + case LOADING_FIRMWARE: > >> + op = ipe_operation_firmware; > >> + break; > >> + case LOADING_MODULE: > >> + op = ipe_operation_kernel_module; > >> + break; > >> + case LOADING_KEXEC_INITRAMFS: > >> + op = ipe_operation_kexec_initramfs; > >> + break; > >> + case LOADING_KEXEC_IMAGE: > >> + op = ipe_operation_kexec_image; > >> + break; > >> + case LOADING_POLICY: > >> + op = ipe_operation_ima_policy; > >> + break; > >> + case LOADING_X509_CERTIFICATE: > >> + op = ipe_operation_ima_x509; > >> + break; > >> + default: > >> + op = ipe_operation_max; > >> + } > >> + > >> + return ipe_process_event(NULL, op, ipe_hook_kernel_load); > >> +} > >> diff --git a/security/ipe/hooks.h b/security/ipe/hooks.h > >> index 58ed4a612e26..c99a0b7f45f7 100644 > >> --- a/security/ipe/hooks.h > >> +++ b/security/ipe/hooks.h > >> @@ -5,11 +5,19 @@ > >> #ifndef IPE_HOOKS_H > >> #define IPE_HOOKS_H > >> > >> +#include <linux/fs.h> > >> #include <linux/types.h> > >> #include <linux/sched.h> > >> +#include <linux/binfmts.h> > >> +#include <linux/security.h> > >> > >> enum ipe_hook { > >> - ipe_hook_max = 0 > >> + ipe_hook_exec = 0, > >> + ipe_hook_mmap, > >> + ipe_hook_mprotect, > >> + ipe_hook_kernel_read, > >> + ipe_hook_kernel_load, > >> + ipe_hook_max > >> }; > >> > >> int ipe_task_alloc(struct task_struct *task, > >> @@ -17,4 +25,17 @@ int ipe_task_alloc(struct task_struct *task, > >> > >> void ipe_task_free(struct task_struct *task); > >> > >> +int ipe_on_exec(struct linux_binprm *bprm); > >> + > >> +int ipe_on_mmap(struct file *f, unsigned long reqprot, unsigned long prot, > >> + unsigned long flags); > >> + > >> +int ipe_on_mprotect(struct vm_area_struct *vma, unsigned long reqprot, > >> + unsigned long prot); > >> + > >> +int ipe_on_kernel_read(struct file *file, enum kernel_read_file_id id, > >> + bool contents); > >> + > >> +int ipe_on_kernel_load_data(enum kernel_load_data_id id, bool contents); > >> + > >> #endif /* IPE_HOOKS_H */ > >> diff --git a/security/ipe/ipe.c b/security/ipe/ipe.c > >> index b58b372327a1..3f9d43783293 100644 > >> --- a/security/ipe/ipe.c > >> +++ b/security/ipe/ipe.c > >> @@ -25,6 +25,11 @@ struct lsm_blob_sizes ipe_blobs __lsm_ro_after_init = > { > >> static struct security_hook_list ipe_hooks[] __lsm_ro_after_init = { > >> LSM_HOOK_INIT(task_alloc, ipe_task_alloc), > >> LSM_HOOK_INIT(task_free, ipe_task_free), > >> + LSM_HOOK_INIT(bprm_check_security, ipe_on_exec), > >> + LSM_HOOK_INIT(mmap_file, ipe_on_mmap), > >> + LSM_HOOK_INIT(file_mprotect, ipe_on_mprotect), > >> + LSM_HOOK_INIT(kernel_read_file, ipe_on_kernel_read), > >> + LSM_HOOK_INIT(kernel_load_data, ipe_on_kernel_load_data), > >> }; > >> > >> /** > >> diff --git a/security/ipe/policy.c b/security/ipe/policy.c > >> index b766824cc08f..048500229365 100644 > >> --- a/security/ipe/policy.c > >> +++ b/security/ipe/policy.c > >> @@ -483,6 +483,14 @@ int ipe_parse_op(const struct ipe_policy_token > *tok, > >> { > >> substring_t match[MAX_OPT_ARGS] = { 0 }; > >> const match_table_t ops = { > >> + { ipe_operation_exec, "EXECUTE" }, > >> + { ipe_operation_firmware, "FIRMWARE" }, > >> + { ipe_operation_kernel_module, "KMODULE" }, > >> + { ipe_operation_kexec_image, "KEXEC_IMAGE" }, > >> + { ipe_operation_kexec_initramfs, "KEXEC_INITRAMFS"}, > >> + { ipe_operation_ima_policy, "IMA_POLICY" }, > >> + { ipe_operation_ima_x509, "IMA_X509_CERT" }, > >> + { ipe_op_alias_kernel_read, "KERNEL_READ" }, > >> { ipe_op_alias_max, NULL }, > >> }; > >> > >> @@ -838,6 +846,15 @@ static int parse_policy(struct ipe_policy *p) > >> return rc; > >> } > >> > >> +static const enum ipe_operation alias_kread[] = { > >> + ipe_operation_firmware, > >> + ipe_operation_kernel_module, > >> + ipe_operation_ima_policy, > >> + ipe_operation_ima_x509, > >> + ipe_operation_kexec_image, > >> + ipe_operation_kexec_initramfs, > >> +}; > >> + > >> /** > >> * ipe_is_op_alias: Determine if @op is an alias for one or more operations > >> * @op: Supplies the operation to check. Should be either ipe_operation or > >> @@ -852,9 +869,15 @@ static int parse_policy(struct ipe_policy *p) > >> bool ipe_is_op_alias(int op, const enum ipe_operation **map, size_t *size) > >> { > >> switch (op) { > >> + case ipe_op_alias_kernel_read: > >> + *map = alias_kread; > >> + *size = ARRAY_SIZE(alias_kread); > >> + break; > >> default: > >> return false; > >> } > >> + > >> + return true; > >> } > >> > >> /** > >> diff --git a/security/ipe/policy.h b/security/ipe/policy.h > >> index 6818f6405dd0..ca37af46e5af 100644 > >> --- a/security/ipe/policy.h > >> +++ b/security/ipe/policy.h > >> @@ -26,7 +26,14 @@ struct ipe_policy_line { > >> struct ipe_module; > >> > >> enum ipe_operation { > >> - ipe_operation_max = 0, > >> + ipe_operation_exec = 0, > >> + ipe_operation_firmware, > >> + ipe_operation_kernel_module, > >> + ipe_operation_kexec_image, > >> + ipe_operation_kexec_initramfs, > >> + ipe_operation_ima_policy, > >> + ipe_operation_ima_x509, > >> + ipe_operation_max > >> }; > >> > >> /* > >> @@ -34,7 +41,8 @@ enum ipe_operation { > >> * that are just one or more operations under the hood > >> */ > >> enum ipe_op_alias { > >> - ipe_op_alias_max = ipe_operation_max, > >> + ipe_op_alias_kernel_read = ipe_operation_max, > >> + ipe_op_alias_max, > >> }; > >> > >> enum ipe_action { > >> -- > >> 2.33.0
