diff --git a/gcc/analyzer/engine.cc b/gcc/analyzer/engine.cc
index fde8412bc15709331f383a89b5c03cb495ca08a2..44ff20cf9af748f9d46d89689bc899c9940e2090 100644
--- a/gcc/analyzer/engine.cc
+++ b/gcc/analyzer/engine.cc
@@ -179,7 +179,7 @@ on_liveness_change (const svalue_set &live_svalues,
const region_model *model)
{
for (sm_state_map *smap : m_new_state->m_checker_states)
- smap->on_liveness_change (live_svalues, model, this);
+ smap->on_liveness_change (live_svalues, model, m_ext_state, this);
}
void
diff --git a/gcc/analyzer/program-state.cc b/gcc/analyzer/program-state.cc
index 888f2a9c40b961f7ed4ef2e40053499aff7bfaef..55dd6ca716674ce645be46565e8412bd236e0764 100644
--- a/gcc/analyzer/program-state.cc
+++ b/gcc/analyzer/program-state.cc
@@ -560,9 +560,10 @@ sm_state_map::on_svalue_leak (const svalue *sval,
{
if (state_machine::state_t state = get_state (sval, ctxt->m_ext_state))
{
- if (!m_sm.can_purge_p (state))
+ if (m_sm.can_purge_p (state))
+ m_map.remove (sval);
+ else
ctxt->on_state_leak (m_sm, sval, state);
- m_map.remove (sval);
}
}
@@ -572,6 +573,7 @@ sm_state_map::on_svalue_leak (const svalue *sval,
void
sm_state_map::on_liveness_change (const svalue_set &live_svalues,
const region_model *model,
+ const extrinsic_state &ext_state,
impl_region_model_context *ctxt)
{
svalue_set svals_to_unset;
@@ -605,9 +607,68 @@ sm_state_map::on_liveness_change (const svalue_set &live_svalues,
ctxt->on_state_leak (m_sm, sval, e.m_state);
}
+ sm_state_map old_sm_map = *this;
+
for (svalue_set::iterator iter = svals_to_unset.begin ();
iter != svals_to_unset.end (); ++iter)
m_map.remove (*iter);
+
+ /* For state machines like "taint" where states can be
+ alt-inherited from other svalues, ensure that state purging doesn't
+ make us lose sm-state.
+
+ Consider e.g.:
+
+ make_tainted(foo);
+ if (foo.field > 128)
+ return;
+ arr[foo.field].f1 = v1;
+
+ where the last line is:
+
+ (A): _t1 = foo.field;
+ (B): _t2 = _t1 * sizeof(arr[0]);
+ (C): [arr + _t2].f1 = val;
+
+ At (A), foo is 'tainted' and foo.field is 'has_ub'.
+ After (B), foo.field's value (in _t1) is no longer directly
+ within LIVE_SVALUES, so with state purging enabled, we would
+ erroneously purge the "has_ub" state from the svalue.
+
+ Given that _t2's value's state comes from _t1's value's state,
+ we need to preserve that information.
+
+ Hence for all svalues that have had their explicit sm-state unset,
+ having their sm-state being unset, determine if doing so has changed
+ their effective state, and if so, explicitly set their state.
+
+ For example, in the above, unsetting the "has_ub" for _t1's value means
+ that _t2's effective value changes from "has_ub" (from alt-inherited
+ from _t1's value) to "tainted" (inherited from "foo"'s value).
+
+ For such cases, preserve the effective state by explicitly setting the
+ new state. In the above example, this means explicitly setting _t2's
+ value to the value ("has_ub") it was previously alt-inheriting from _t1's
+ value. */
+ if (m_sm.has_alt_get_inherited_state_p ())
+ {
+ auto_vec<const svalue *> svalues_needing_state;
+ for (auto unset_sval : svals_to_unset)
+ {
+ const state_machine::state_t old_state
+ = old_sm_map.get_state (unset_sval, ext_state);
+ const state_machine::state_t new_state
+ = get_state (unset_sval, ext_state);
+ if (new_state != old_state)
+ svalues_needing_state.safe_push (unset_sval);
+ }
+ for (auto sval : svalues_needing_state)
+ {
+ const state_machine::state_t old_state
+ = old_sm_map.get_state (sval, ext_state);
+ impl_set_state (sval, old_state, nullptr, ext_state);
+ }
+ }
}
/* Purge state from SVAL (in response to a call to an unknown function). */
diff --git a/gcc/analyzer/program-state.h b/gcc/analyzer/program-state.h
index 50bf2ab277a80b15d645635b2db39ccb141fe7cf..69bf931f070caca6033ba79344b6ca8e8653cdee 100644
--- a/gcc/analyzer/program-state.h
+++ b/gcc/analyzer/program-state.h
@@ -155,6 +155,7 @@ public:
impl_region_model_context *ctxt);
void on_liveness_change (const svalue_set &live_svalues,
const region_model *model,
+ const extrinsic_state &ext_state,
impl_region_model_context *ctxt);
void on_unknown_change (const svalue *sval,
diff --git a/gcc/analyzer/sm-taint.cc b/gcc/analyzer/sm-taint.cc
index dc4b078c411f6030c4a2c42a6e6facac50044ba4..bbf683f82efc6fe211600ba0eca52ffc2c885ac4 100644
--- a/gcc/analyzer/sm-taint.cc
+++ b/gcc/analyzer/sm-taint.cc
@@ -86,6 +86,12 @@ public:
const extrinsic_state &ext_state)
const final override;
+ bool
+ has_alt_get_inherited_state_p () const final override
+ {
+ return true;
+ }
+
bool on_stmt (sm_context *sm_ctxt,
const supernode *node,
const gimple *stmt) const final override;
@@ -1199,6 +1205,9 @@ taint_state_machine::on_bounded_ranges (sm_context *sm_ctxt,
bool
taint_state_machine::can_purge_p (state_t s ATTRIBUTE_UNUSED) const
{
+ if (s == m_has_lb || s == m_has_ub)
+ return false;
+
return true;
}
diff --git a/gcc/analyzer/sm.h b/gcc/analyzer/sm.h
index e7f634f4245573cbec1845e793d969357deb6a28..a58f5dbc395334f14a9bb1349e1a8e06f88cefc5 100644
--- a/gcc/analyzer/sm.h
+++ b/gcc/analyzer/sm.h
@@ -78,6 +78,12 @@ public:
return NULL;
}
+ virtual bool
+ has_alt_get_inherited_state_p () const
+ {
+ return false;
+ }
+
virtual state_machine::state_t get_default_state (const svalue *) const
{
return m_start;
diff --git a/gcc/testsuite/gcc.dg/plugin/plugin.exp b/gcc/testsuite/gcc.dg/plugin/plugin.exp
index a5a72daac1a5db70845c0f862d6815627ef24e71..8141cc2aa46d1a522715cde4acf9c65aa5bfbb7f 100644
--- a/gcc/testsuite/gcc.dg/plugin/plugin.exp
+++ b/gcc/testsuite/gcc.dg/plugin/plugin.exp
@@ -170,7 +170,8 @@ set plugin_test_list [list \
taint-pr112850-precise.c \
taint-pr112850-too-complex.c \
taint-pr112850-unsanitized.c \
- taint-pr112927.c } \
+ taint-pr112927.c \
+ taint-pr112977.c } \
{ analyzer_cpython_plugin.c \
cpython-plugin-test-no-Python-h.c \
cpython-plugin-test-PyList_Append.c \
diff --git a/gcc/testsuite/gcc.dg/plugin/taint-pr112977.c b/gcc/testsuite/gcc.dg/plugin/taint-pr112977.c
new file mode 100644
index 0000000000000000000000000000000000000000..a9beb00b88dc135d953f22d2c2c115416dd6811a
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/plugin/taint-pr112977.c
@@ -0,0 +1,44 @@
+/* Reduced from false positive in Linux kernel in
+ drivers/scsi/aacraid/aachba.c. */
+
+/* { dg-do compile } */
+/* { dg-options "-fanalyzer" } */
+/* { dg-require-effective-target analyzer } */
+
+typedef unsigned char u8;
+typedef unsigned int u32;
+
+extern unsigned long
+copy_from_user(void* to, const void* from, unsigned long n);
+
+struct fsa_dev_info
+{
+ u8 valid;
+ u8 deleted;
+};
+struct aac_dev
+{
+ int maximum_num_containers;
+ struct fsa_dev_info* fsa_dev;
+};
+struct aac_delete_disk
+{
+ u32 disknum;
+ u32 cnum;
+};
+int
+force_delete_disk(struct aac_dev* dev, void* arg)
+{
+ struct aac_delete_disk dd;
+ struct fsa_dev_info* fsa_dev_ptr;
+ fsa_dev_ptr = dev->fsa_dev;
+ if (!fsa_dev_ptr)
+ return -16;
+ if (copy_from_user(&dd, arg, sizeof(struct aac_delete_disk)))
+ return -14;
+ if (dd.cnum >= dev->maximum_num_containers)
+ return -22;
+ fsa_dev_ptr[dd.cnum].deleted = 1;
+ fsa_dev_ptr[dd.cnum].valid = 0; /* { dg-bogus "use of attacker-controlled value as offset without upper-bounds checking" } */
+ return 0;
+}