modbuildid is never set when kallsyms_lookup_buildid is returning via successful bpf_address_lookup or ftrace_mod_address_lookup.
This leads to an uninitialized pointer dereference on x86 when CONFIG_STACKTRACE_BUILD_ID=y inside __sprint_symbol. Prevent this by always initializing modbuildid. Closes: https://bugzilla.kernel.org/show_bug.cgi?id=220717 Signed-off-by: Maurice Hieronymus <[email protected]> --- include/linux/filter.h | 6 ++++-- include/linux/ftrace.h | 4 ++-- kernel/kallsyms.c | 4 ++-- kernel/trace/ftrace.c | 4 +++- 4 files changed, 11 insertions(+), 7 deletions(-) diff --git a/include/linux/filter.h b/include/linux/filter.h index fd54fed8f95f..eb1d1c876503 100644 --- a/include/linux/filter.h +++ b/include/linux/filter.h @@ -1384,12 +1384,14 @@ struct bpf_prog *bpf_prog_ksym_find(unsigned long addr); static inline int bpf_address_lookup(unsigned long addr, unsigned long *size, - unsigned long *off, char **modname, char *sym) + unsigned long *off, char **modname, const unsigned char **modbuildid, char *sym) { int ret = __bpf_address_lookup(addr, size, off, sym); if (ret && modname) *modname = NULL; + if (ret && modbuildid) + *modbuildid = NULL; return ret; } @@ -1455,7 +1457,7 @@ static inline struct bpf_prog *bpf_prog_ksym_find(unsigned long addr) static inline int bpf_address_lookup(unsigned long addr, unsigned long *size, - unsigned long *off, char **modname, char *sym) + unsigned long *off, char **modname, const unsigned char **modbuildid, char *sym) { return 0; } diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 770f0dc993cc..ed673fa2536b 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -87,11 +87,11 @@ struct ftrace_hash; defined(CONFIG_DYNAMIC_FTRACE) int ftrace_mod_address_lookup(unsigned long addr, unsigned long *size, - unsigned long *off, char **modname, char *sym); + unsigned long *off, char **modname, const unsigned char **modbuildid, char *sym); #else static inline int ftrace_mod_address_lookup(unsigned long addr, unsigned long *size, - unsigned long *off, char **modname, char *sym) + unsigned long *off, char **modname, const unsigned char **modbuildid, char *sym) { return 0; } diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c index 049e296f586c..b1516d3fa9c5 100644 --- a/kernel/kallsyms.c +++ b/kernel/kallsyms.c @@ -378,11 +378,11 @@ static int kallsyms_lookup_buildid(unsigned long addr, modname, modbuildid, namebuf); if (!ret) ret = bpf_address_lookup(addr, symbolsize, - offset, modname, namebuf); + offset, modname, modbuildid, namebuf); if (!ret) ret = ftrace_mod_address_lookup(addr, symbolsize, - offset, modname, namebuf); + offset, modname, modbuildid, namebuf); return ret; } diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 3ec2033c0774..63a926926709 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -7749,7 +7749,7 @@ ftrace_func_address_lookup(struct ftrace_mod_map *mod_map, int ftrace_mod_address_lookup(unsigned long addr, unsigned long *size, - unsigned long *off, char **modname, char *sym) + unsigned long *off, char **modname, const unsigned char **modbuildid, char *sym) { struct ftrace_mod_map *mod_map; int ret = 0; @@ -7761,6 +7761,8 @@ ftrace_mod_address_lookup(unsigned long addr, unsigned long *size, if (ret) { if (modname) *modname = mod_map->mod->name; + if (modbuildid) + *modbuildid = mod_map->mod->build_id; break; } } base-commit: 0048fbb4011ec55c32d3148b2cda56433f273375 -- 2.50.1
