Merge tag 'kallsyms_show_value-v5.8-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull kallsyms fix from Kees Cook:
 "Refactor kallsyms_show_value() users for correct cred.

  I'm not delighted by the timing of getting these changes to you, but
  it does fix a handful of kernel address exposures, and no one has
  screamed yet at the patches.

  Several users of kallsyms_show_value() were performing checks not
  during "open". Refactor everything needed to gain proper checks
  against file->f_cred for modules, kprobes, and bpf"

* tag 'kallsyms_show_value-v5.8-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  selftests: kmod: Add module address visibility test
  bpf: Check correct cred for CAP_SYSLOG in bpf_dump_raw_ok()
  kprobes: Do not expose probe addresses to non-CAP_SYSLOG
  module: Do not expose section addresses to non-CAP_SYSLOG
  module: Refactor section attr into bin attribute
  kallsyms: Refactor kallsyms_show_value() to take cred

2 files changed, 5 insertions, 4 deletions

diff --git a/include/linux/filter.h b/include/linux/filter.h
index 259377723603..0b0144752d78 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -884,12 +884,12 @@ void bpf_jit_compile(struct bpf_prog *prog);
 bool bpf_jit_needs_zext(void);
 bool bpf_helper_changes_pkt_data(void *func);
 
-static inline bool bpf_dump_raw_ok(void)
+static inline bool bpf_dump_raw_ok(const struct cred *cred)
 {
 	/* Reconstruction of call-sites is dependent on kallsyms,
 	 * thus make dump the same restriction.
 	 */
-	return kallsyms_show_value() == 1;
+	return kallsyms_show_value(cred);
 }
 
 struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off,
diff --git a/include/linux/kallsyms.h b/include/linux/kallsyms.h
index 98338dc6b5d2..481273f0c72d 100644
--- a/include/linux/kallsyms.h
+++ b/include/linux/kallsyms.h
@@ -18,6 +18,7 @@
 #define KSYM_SYMBOL_LEN (sizeof("%s+%#lx/%#lx [%s]") + (KSYM_NAME_LEN - 1) + \
 			 2*(BITS_PER_LONG*3/10) + (MODULE_NAME_LEN - 1) + 1)
 
+struct cred;
 struct module;
 
 static inline int is_kernel_inittext(unsigned long addr)
@@ -98,7 +99,7 @@ int lookup_symbol_name(unsigned long addr, char *symname);
 int lookup_symbol_attrs(unsigned long addr, unsigned long *size, unsigned long *offset, char *modname, char *name);
 
 /* How and when do we show kallsyms values? */
-extern int kallsyms_show_value(void);
+extern bool kallsyms_show_value(const struct cred *cred);
 
 #else /* !CONFIG_KALLSYMS */
 
@@ -158,7 +159,7 @@ static inline int lookup_symbol_attrs(unsigned long addr, unsigned long *size, u
 	return -ERANGE;
 }
 
-static inline int kallsyms_show_value(void)
+static inline bool kallsyms_show_value(const struct cred *cred)
 {
 	return false;
 }