| Message ID | 20211012022521.399302-1-iii@linux.ibm.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Delegated to: | BPF |
| Headers | show |
| Series | [dwarves] dwarf_loader: Fix heap overflow when accessing variable specification | expand |
| Context | Check | Description |
|---|---|---|
| netdev/tree_selection | success | Not a local patch |
Em Tue, Oct 12, 2021 at 04:25:21AM +0200, Ilya Leoshkevich escreveu: > Variables can be allocated with or without specification, however, > tag__recode_dwarf_type() always tries accessing it, leading to heap > read overflows and subsequent logic bugs. > > Fix by introducing a bit that tracks whether or not specification is > present. Thanks, applied. - Arnaldo > Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> > --- > dwarf_loader.c | 15 ++++++++++----- > dwarves.h | 1 + > 2 files changed, 11 insertions(+), 5 deletions(-) > > diff --git a/dwarf_loader.c b/dwarf_loader.c > index 48e1bf0..60bdca3 100644 > --- a/dwarf_loader.c > +++ b/dwarf_loader.c > @@ -723,6 +723,7 @@ static struct variable *variable__new(Dwarf_Die *die, struct cu *cu, struct conf > var->external = dwarf_hasattr(die, DW_AT_external); > /* non-defining declaration of an object */ > var->declaration = dwarf_hasattr(die, DW_AT_declaration); > + var->has_specification = has_specification; > var->scope = VSCOPE_UNKNOWN; > INIT_LIST_HEAD(&var->annots); > var->ip.addr = 0; > @@ -2291,12 +2292,16 @@ static int tag__recode_dwarf_type(struct tag *tag, struct cu *cu) > goto find_type; > case DW_TAG_variable: { > struct variable *var = tag__variable(tag); > - dwarf_off_ref specification = dwarf_tag__spec(dtag); > > - if (specification.off) { > - dtype = dwarf_cu__find_tag_by_ref(cu->priv, &specification); > - if (dtype) > - var->spec = tag__variable(dtype->tag); > + if (var->has_specification) { > + dwarf_off_ref specification = dwarf_tag__spec(dtag); > + > + if (specification.off) { > + dtype = dwarf_cu__find_tag_by_ref(cu->priv, > + &specification); > + if (dtype) > + var->spec = tag__variable(dtype->tag); > + } > } > } > > diff --git a/dwarves.h b/dwarves.h > index 30d33fa..20608dd 100644 > --- a/dwarves.h > +++ b/dwarves.h > @@ -691,6 +691,7 @@ struct variable { > const char *name; > uint8_t external:1; > uint8_t declaration:1; > + uint8_t has_specification:1; > enum vscope scope; > struct location location; > struct hlist_node tool_hnode; > -- > 2.31.1
diff --git a/dwarf_loader.c b/dwarf_loader.c index 48e1bf0..60bdca3 100644 --- a/dwarf_loader.c +++ b/dwarf_loader.c @@ -723,6 +723,7 @@ static struct variable *variable__new(Dwarf_Die *die, struct cu *cu, struct conf var->external = dwarf_hasattr(die, DW_AT_external); /* non-defining declaration of an object */ var->declaration = dwarf_hasattr(die, DW_AT_declaration); + var->has_specification = has_specification; var->scope = VSCOPE_UNKNOWN; INIT_LIST_HEAD(&var->annots); var->ip.addr = 0; @@ -2291,12 +2292,16 @@ static int tag__recode_dwarf_type(struct tag *tag, struct cu *cu) goto find_type; case DW_TAG_variable: { struct variable *var = tag__variable(tag); - dwarf_off_ref specification = dwarf_tag__spec(dtag); - if (specification.off) { - dtype = dwarf_cu__find_tag_by_ref(cu->priv, &specification); - if (dtype) - var->spec = tag__variable(dtype->tag); + if (var->has_specification) { + dwarf_off_ref specification = dwarf_tag__spec(dtag); + + if (specification.off) { + dtype = dwarf_cu__find_tag_by_ref(cu->priv, + &specification); + if (dtype) + var->spec = tag__variable(dtype->tag); + } } } diff --git a/dwarves.h b/dwarves.h index 30d33fa..20608dd 100644 --- a/dwarves.h +++ b/dwarves.h @@ -691,6 +691,7 @@ struct variable { const char *name; uint8_t external:1; uint8_t declaration:1; + uint8_t has_specification:1; enum vscope scope; struct location location; struct hlist_node tool_hnode;
Variables can be allocated with or without specification, however, tag__recode_dwarf_type() always tries accessing it, leading to heap read overflows and subsequent logic bugs. Fix by introducing a bit that tracks whether or not specification is present. Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com> --- dwarf_loader.c | 15 ++++++++++----- dwarves.h | 1 + 2 files changed, 11 insertions(+), 5 deletions(-)