Generated YNL code does not check the return value of malloc() and calloc() before passing the resulting pointer to memcpy(). This could lead to a NULL pointer dereference on memory allocation failure. Updated the C code generator to check for allocation failures and to return an error code when applicable, or to return with no error code for a user to check for a NULL in the field that allocation was attempted for. Signed-off-by: Thaison Phan --- tools/net/ynl/pyynl/ynl_gen_c.py | 53 ++++++++++++++++++++++---------- 1 file changed, 37 insertions(+), 16 deletions(-) diff --git a/tools/net/ynl/pyynl/ynl_gen_c.py b/tools/net/ynl/pyynl/ynl_gen_c.py index 2fd68c738075..a323acdc42ba 100755 --- a/tools/net/ynl/pyynl/ynl_gen_c.py +++ b/tools/net/ynl/pyynl/ynl_gen_c.py @@ -526,16 +526,20 @@ class TypeString(Type): def _attr_get(self, ri, var): len_mem = var + '->_len.' + self.c_name - return [f"{len_mem} = len;", - f"{var}->{self.c_name} = malloc(len + 1);", + return [f"{var}->{self.c_name} = malloc(len + 1);", + f"if (!{var}->{self.c_name})", + "return YNL_PARSE_CB_ERROR;", + f"{len_mem} = len;", f"memcpy({var}->{self.c_name}, ynl_attr_get_str(attr), len);", f"{var}->{self.c_name}[len] = 0;"], \ ['len = strnlen(ynl_attr_get_str(attr), ynl_attr_data_len(attr));'], \ ['unsigned int len;'] def _setter_lines(self, ri, member, presence): - return [f"{presence} = strlen({self.c_name});", - f"{member} = malloc({presence} + 1);", + return [f"{member} = malloc(strlen({self.c_name}) + 1);", + f"if (!{member})", + "return;", + f"{presence} = strlen({self.c_name});", f'memcpy({member}, {self.c_name}, {presence});', f'{member}[{presence}] = 0;'] @@ -582,15 +586,19 @@ class TypeBinary(Type): def _attr_get(self, ri, var): len_mem = var + '->_len.' + self.c_name - return [f"{len_mem} = len;", - f"{var}->{self.c_name} = malloc(len);", + return [f"{var}->{self.c_name} = malloc(len);", + f"if (!{var}->{self.c_name})", + "return YNL_PARSE_CB_ERROR;", + f"{len_mem} = len;", f"memcpy({var}->{self.c_name}, ynl_attr_data(attr), len);"], \ ['len = ynl_attr_data_len(attr);'], \ ['unsigned int len;'] def _setter_lines(self, ri, member, presence): - return [f"{presence} = len;", - f"{member} = malloc({presence});", + return [f"{member} = malloc(len);", + f"if (!{member})", + "return;", + f"{presence} = len;", f'memcpy({member}, {self.c_name}, {presence});'] @@ -601,11 +609,13 @@ class TypeBinaryStruct(TypeBinary): def _attr_get(self, ri, var): struct_sz = 'sizeof(struct ' + c_lower(self.get("struct")) + ')' len_mem = var + '->_' + self.presence_type() + '.' + self.c_name - return [f"{len_mem} = len;", - f"if (len < {struct_sz})", + return [f"if (len < {struct_sz})", f"{var}->{self.c_name} = calloc(1, {struct_sz});", "else", f"{var}->{self.c_name} = malloc(len);", + f"if (!{var}->{self.c_name})", + "return YNL_PARSE_CB_ERROR;", + f"{len_mem} = len;", f"memcpy({var}->{self.c_name}, ynl_attr_data(attr), len);"], \ ['len = ynl_attr_data_len(attr);'], \ ['unsigned int len;'] @@ -631,18 +641,21 @@ class TypeBinaryScalarArray(TypeBinary): def _attr_get(self, ri, var): len_mem = var + '->_count.' + self.c_name - return [f"{len_mem} = len / sizeof(__{self.get('sub-type')});", - f"len = {len_mem} * sizeof(__{self.get('sub-type')});", + return [f"len = (len / sizeof(__{self.get('sub-type')})) * sizeof(__{self.get('sub-type')});", f"{var}->{self.c_name} = malloc(len);", + f"if (!{var}->{self.c_name})", + "return YNL_PARSE_CB_ERROR;", + f"{len_mem} = len / sizeof(__{self.get('sub-type')});", f"memcpy({var}->{self.c_name}, ynl_attr_data(attr), len);"], \ ['len = ynl_attr_data_len(attr);'], \ ['unsigned int len;'] def _setter_lines(self, ri, member, presence): - return [f"{presence} = count;", - f"count *= sizeof(__{self.get('sub-type')});", - f"{member} = malloc(count);", - f'memcpy({member}, {self.c_name}, count);'] + return [f"{member} = malloc(count * sizeof(__{self.get('sub-type')}));", + f"if (!{member})", + "return;", + f"{presence} = count;", + f'memcpy({member}, {self.c_name}, count * sizeof(__{self.get("sub-type")}));'] class TypeBitfield32(Type): @@ -2227,6 +2240,8 @@ def _multi_parse(ri, struct, init_lines, local_vars): ri.cw.block_start(line=f"if (n_{aspec.c_name})") ri.cw.p(f"dst->{aspec.c_name} = calloc(n_{aspec.c_name}, sizeof(*dst->{aspec.c_name}));") + ri.cw.p(f"if (!dst->{aspec.c_name})") + ri.cw.p("return YNL_PARSE_CB_ERROR;") ri.cw.p(f"dst->_count.{aspec.c_name} = n_{aspec.c_name};") ri.cw.p('i = 0;') if 'nested-attributes' in aspec: @@ -2252,6 +2267,8 @@ def _multi_parse(ri, struct, init_lines, local_vars): aspec = struct[arg] ri.cw.block_start(line=f"if (n_{aspec.c_name})") ri.cw.p(f"dst->{aspec.c_name} = calloc(n_{aspec.c_name}, sizeof(*dst->{aspec.c_name}));") + ri.cw.p(f"if (!dst->{aspec.c_name})") + ri.cw.p("return YNL_PARSE_CB_ERROR;") ri.cw.p(f"dst->_count.{aspec.c_name} = n_{aspec.c_name};") ri.cw.p('i = 0;') if 'nested-attributes' in aspec: @@ -2275,6 +2292,8 @@ def _multi_parse(ri, struct, init_lines, local_vars): ri.cw.nl() ri.cw.p('len = strnlen(ynl_attr_get_str(attr), ynl_attr_data_len(attr));') ri.cw.p(f'dst->{aspec.c_name}[i] = malloc(sizeof(struct ynl_string) + len + 1);') + ri.cw.p(f"if (!dst->{aspec.c_name}[i])") + ri.cw.p("return YNL_PARSE_CB_ERROR;") ri.cw.p(f"dst->{aspec.c_name}[i]->len = len;") ri.cw.p(f"memcpy(dst->{aspec.c_name}[i]->str, ynl_attr_get_str(attr), len);") ri.cw.p(f"dst->{aspec.c_name}[i]->str[len] = 0;") @@ -2434,6 +2453,8 @@ def print_req(ri): if 'reply' in ri.op[ri.op_mode]: ri.cw.p('rsp = calloc(1, sizeof(*rsp));') + ri.cw.p('if (!rsp)') + ri.cw.p(f'return {ret_err};') ri.cw.p('yrs.yarg.data = rsp;') ri.cw.p(f"yrs.cb = {op_prefix(ri, 'reply')}_parse;") if ri.op.value is not None: -- 2.55.0.571.g244d577d93-goog