[Devel] [VZ10 02/21] ve/vma: Fix NULL dereference when accessing ve->vdso_image_*

[Vladimir Riabchun]

With !CONFIG_VE get_exec_env() returns NULL, all accesses to
vdso fields are done without config check.
Add helpers that return pointers to vdso_image_{32,64} objects
when !CONFIG_VE.

https://virtuozzo.atlassian.net/browse/VSTOR-130116

Feature: !CONFIG_VE build
Signed-off-by: Vladimir Riabchun <vladimir.riabchun at virtuozzo.com>
---
 arch/x86/entry/vdso/vma.c    |  6 +++---
 arch/x86/kernel/process_64.c |  4 ++--
 include/linux/ve.h           | 20 ++++++++++++++++++++
 3 files changed, 25 insertions(+), 5 deletions(-)

diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c
index 6427a3a10d15..04b5134362eb 100644
--- a/arch/x86/entry/vdso/vma.c
+++ b/arch/x86/entry/vdso/vma.c
@@ -80,7 +80,7 @@ static void vdso_fix_landing(const struct vdso_image *image,
 		struct vm_area_struct *new_vma)
 {
 #if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
-	if (in_ia32_syscall() && image == get_exec_env()->vdso_32) {
+	if (in_ia32_syscall() && image == ve_get_vdso_32(get_exec_env())) {
 		struct pt_regs *regs = current_pt_regs();
 		unsigned long vdso_land = image->sym_int80_landing_pad;
 		unsigned long old_land_addr = vdso_land +
@@ -310,7 +310,7 @@ static int load_vdso32(void)
 	if (vdso32_enabled != 1)  /* Other values all mean "disabled" */
 		return 0;
 
-	return map_vdso(get_exec_env()->vdso_32, 0);
+	return map_vdso(ve_get_vdso_32(get_exec_env()), 0);
 }
 #endif
 
@@ -320,7 +320,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 	if (!vdso64_enabled)
 		return 0;
 
-	return map_vdso(get_exec_env()->vdso_64, 0);
+	return map_vdso(ve_get_vdso_64(get_exec_env()), 0);
 }
 
 #ifdef CONFIG_COMPAT
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index 18a02b62cc37..3761380d68da 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -945,10 +945,10 @@ long do_arch_prctl_64(struct task_struct *task, int option, unsigned long arg2)
 # endif
 # if defined CONFIG_X86_32 || defined CONFIG_IA32_EMULATION
 	case ARCH_MAP_VDSO_32:
-		return prctl_map_vdso(get_exec_env()->vdso_32, arg2);
+		return prctl_map_vdso(ve_get_vdso_32(get_exec_env()), arg2);
 # endif
 	case ARCH_MAP_VDSO_64:
-		return prctl_map_vdso(get_exec_env()->vdso_64, arg2);
+		return prctl_map_vdso(ve_get_vdso_64(get_exec_env()), arg2);
 #endif
 #ifdef CONFIG_ADDRESS_MASKING
 	case ARCH_GET_UNTAG_MASK:
diff --git a/include/linux/ve.h b/include/linux/ve.h
index 224acf012821..c64860664b62 100644
--- a/include/linux/ve.h
+++ b/include/linux/ve.h
@@ -279,6 +279,16 @@ extern bool is_ve_init_net(const struct net *net);
 
 void ve_setup_task(struct task_struct *p, struct ve_struct *ve);
 
+static inline struct vdso_image *ve_get_vdso_32(struct ve_struct *ve)
+{
+	return ve->vdso_32;
+}
+
+static inline struct vdso_image *ve_get_vdso_64(struct ve_struct *ve)
+{
+	return ve->vdso_64;
+}
+
 #else	/* CONFIG_VE */
 #include <linux/init_task.h>
 #define get_ve(ve)	((void)(ve), NULL)
@@ -336,6 +346,16 @@ static inline int vz_security_protocol_check(struct net *net, int protocol) { re
 
 static inline void ve_setup_task(struct task_struct *p, struct ve_struct *ve) { }
 
+static inline struct vdso_image *ve_get_vdso_32(struct ve_struct *ve)
+{
+	return (struct vdso_image *)&vdso_image_32;
+}
+
+static inline struct vdso_image *ve_get_vdso_64(struct ve_struct *ve)
+{
+	return (struct vdso_image *)&vdso_image_64;
+}
+
 #endif	/* CONFIG_VE */
 
 struct seq_file;
-- 
2.43.0