* [PATCH v2 net-next 2/2] tools: ynl: check alloc fails in generated getter code
2026-08-07 17:14 [PATCH v2 net-next 0/2] update NULL pointer handling in generated code Thaison Phan
2026-08-07 17:14 ` [PATCH v2 net-next 1/2] tools: ynl: check for null ptr on dump free Thaison Phan
@ 2026-08-07 17:15 ` Thaison Phan
1 sibling, 0 replies; 3+ messages in thread
From: Thaison Phan @ 2026-08-07 17:15 UTC (permalink / raw)
To: Jakub Kicinski, Donald Hunter, David S . Miller , Eric Dumazet,
Paolo Abeni
Cc: Simon Horman, Fengyuan Gong, Stan Iliev,
Asbjørn Sloth Tønnesen, Matthieu Baerts (NGI0),
Thaison Phan, netdev, linux-kernel
Generated YNL getter 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 in getters.
Signed-off-by: Thaison Phan <thaisonphan@google.com>
---
v1 -> v2: Removed updates to allocation checks in setters as those can be
fixed in a separate patch. (Suggested by Jakub Kicinski)
v1:
https://lore.kernel.org/netdev/20260803201652.2752685-3-thaisonphan@google.com/
tools/net/ynl/pyynl/ynl_gen_c.py | 32 ++++++++++++++++++++++++--------
1 file changed, 24 insertions(+), 8 deletions(-)
diff --git a/tools/net/ynl/pyynl/ynl_gen_c.py b/tools/net/ynl/pyynl/ynl_gen_c.py
index 95502dbaec94..2b3483db1b60 100755
--- a/tools/net/ynl/pyynl/ynl_gen_c.py
+++ b/tools/net/ynl/pyynl/ynl_gen_c.py
@@ -526,8 +526,10 @@ 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));'], \
@@ -582,8 +584,10 @@ 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;']
@@ -601,11 +605,13 @@ 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;']
@@ -631,9 +637,11 @@ 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;']
@@ -2227,6 +2235,8 @@ 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 +2262,8 @@ 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 +2287,8 @@ 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 +2448,8 @@ 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:
--
2.55.0.654.g21b8a5bc05-goog
^ permalink raw reply related [flat|nested] 3+ messages in thread