kernel: dynamic get_cred_rcu patch for appropriate atomic function and apply patch accordingly

This commit is contained in:
Rifat Azad
2025-01-17 15:17:11 +06:00
parent 3ee1cbe4c2
commit 14624ea966

View File

@@ -60,7 +60,19 @@ ccflags-y += -DKSU_COMPAT_GET_CRED_RCU
ccflags-y += -DKSU_UMOUNT
# This feature is introduced in linux 5.0-rc1
# Determine the appropriate atomic function and apply patch accordingly
ifeq ($(shell grep -q "atomic_inc_not_zero" $(srctree)/kernel/cred.c; echo $$?),0)
ATOMIC_INC_FUNC = atomic_inc_not_zero
else ifeq ($(shell grep -q "atomic_long_inc_not_zero" $(srctree)/kernel/cred.c; echo $$?),0)
ATOMIC_INC_FUNC = atomic_long_inc_not_zero
else
$(info -- KSU_NEXT: Neither atomic_inc_not_zero nor atomic_long_inc_not_zero found in kernel/cred.c)
endif
# Inform which function is being patched
$(info -- KSU_NEXT: Using $(ATOMIC_INC_FUNC) in get_cred_rcu patch.)
# Add the get_cred_rcu function to cred.h if not already present
ifneq ($(shell grep -Eq "^static inline const struct cred \*get_cred_rcu" $(srctree)/include/linux/cred.h; echo $$?),0)
$(info -- KSU_NEXT: adding function 'static inline const struct cred *get_cred_rcu(const struct cred *cred);' to $(srctree)/include/linux/cred.h)
GET_CRED_RCU = static inline const struct cred *get_cred_rcu(const struct cred *cred)\n\
@@ -68,15 +80,16 @@ GET_CRED_RCU = static inline const struct cred *get_cred_rcu(const struct cred *
struct cred *nonconst_cred = (struct cred *) cred;\n\t\
if (!cred)\n\t\t\
return NULL;\n\t\
if (!atomic_inc_not_zero(&nonconst_cred->usage))\n\t\t\
if (!$(ATOMIC_INC_FUNC)(&nonconst_cred->usage))\n\t\t\
return NULL;\n\t\
validate_creds(cred);\n\t\
return cred;\n\
}\n
$(shell grep -qF "$(GET_CRED_RCU)" $(srctree)/include/linux/cred.h || sed -i '/^static inline void put_cred/i $(GET_CRED_RCU)' $(srctree)/include/linux/cred.h)
# Modify get_task_cred in cred.c
$(info -- KSU_NEXT: modifying 'get_task_cred' function in $(srctree)/kernel/cred.c)
$(shell sed -i 's/!atomic_inc_not_zero(&((struct cred \*)cred)->usage)/!get_cred_rcu(cred)/g' $(srctree)/kernel/cred.c)
$(shell sed -i "s/!$(ATOMIC_INC_FUNC)(&((struct cred \*)cred)->usage)/!get_cred_rcu(cred)/g" $(srctree)/kernel/cred.c)
endif
ifneq ($(shell grep -Eq "^static int can_umount" $(srctree)/fs/namespace.c; echo $$?),0)