[gcc/devel/c++-modules] analyzer: fix dedupe issue seen with CVE-2005-1689
Nathan Sidwell
nathan@gcc.gnu.org
Fri Jan 17 19:14:00 GMT 2020
https://gcc.gnu.org/g:14f9d7b9a708ebca57257059bda40986bb1e82a7
commit 14f9d7b9a708ebca57257059bda40986bb1e82a7
Author: David Malcolm <dmalcolm@redhat.com>
Date: Fri Dec 13 19:36:11 2019 -0500
analyzer: fix dedupe issue seen with CVE-2005-1689
Whilst analyzing the reproducer for detecting CVE-2005-1689
(krb5-1.4.1's src/lib/krb5/krb/recvauth.c), the analyzer reported
11 double-free diagnostics on lines of the form:
krb5_xfree(inbuf.data);
with no deduplication occcurring.
The root cause is that the diagnostics each have a COMPONENT_REF for
the inbuf.data, but they are different trees, and the de-duplication
logic was using pointer equality.
This patch replaces the pointer equality tests with calls to a new
pending_diagnostic::same_tree_p, implemented using simple_cst_equal.
With this patch, de-duplication occurs, and only 3 diagnostics are
reported. The 11 diagnostics are partitioned into 3 dedupe keys,
2 with 2 duplicates and 1 with 7 duplicates.
gcc/analyzer/ChangeLog:
* diagnostic-manager.cc (saved_diagnostic::operator==): Move here
from header. Replace pointer equality test on m_var with call to
pending_diagnostic::same_tree_p.
* diagnostic-manager.h (saved_diagnostic::operator==): Move to
diagnostic-manager.cc.
* pending-diagnostic.cc (pending_diagnostic::same_tree_p): New.
* pending-diagnostic.h (pending_diagnostic::same_tree_p): New.
* sm-file.cc (file_diagnostic::subclass_equal_p): Replace pointer
equality on m_arg with call to pending_diagnostic::same_tree_p.
* sm-malloc.cc (malloc_diagnostic::subclass_equal_p): Likewise.
(possible_null_arg::subclass_equal_p): Likewise.
(null_arg::subclass_equal_p): Likewise.
(free_of_non_heap::subclass_equal_p): Likewise.
* sm-pattern-test.cc (pattern_match::operator==): Likewise.
* sm-sensitive.cc (exposure_through_output_file::operator==):
Likewise.
* sm-taint.cc (tainted_array_index::operator==): Likewise.
gcc/testsuite/ChangeLog:
* gcc.dg/analyzer/CVE-2005-1689-dedupe-issue.c: New test.
Diff:
---
gcc/analyzer/ChangeLog | 20 +++++++++++++++++
gcc/analyzer/diagnostic-manager.cc | 14 ++++++++++++
gcc/analyzer/diagnostic-manager.h | 13 +----------
gcc/analyzer/pending-diagnostic.cc | 9 ++++++++
gcc/analyzer/pending-diagnostic.h | 4 ++++
gcc/analyzer/sm-file.cc | 2 +-
gcc/analyzer/sm-malloc.cc | 8 +++----
gcc/analyzer/sm-pattern-test.cc | 4 ++--
gcc/analyzer/sm-sensitive.cc | 2 +-
gcc/analyzer/sm-taint.cc | 2 +-
gcc/testsuite/ChangeLog | 4 ++++
.../gcc.dg/analyzer/CVE-2005-1689-dedupe-issue.c | 26 ++++++++++++++++++++++
12 files changed, 87 insertions(+), 21 deletions(-)
diff --git a/gcc/analyzer/ChangeLog b/gcc/analyzer/ChangeLog
index 4fe354a..9afb288 100644
--- a/gcc/analyzer/ChangeLog
+++ b/gcc/analyzer/ChangeLog
@@ -1,5 +1,25 @@
2020-01-14 David Malcolm <dmalcolm@redhat.com>
+ * diagnostic-manager.cc (saved_diagnostic::operator==): Move here
+ from header. Replace pointer equality test on m_var with call to
+ pending_diagnostic::same_tree_p.
+ * diagnostic-manager.h (saved_diagnostic::operator==): Move to
+ diagnostic-manager.cc.
+ * pending-diagnostic.cc (pending_diagnostic::same_tree_p): New.
+ * pending-diagnostic.h (pending_diagnostic::same_tree_p): New.
+ * sm-file.cc (file_diagnostic::subclass_equal_p): Replace pointer
+ equality on m_arg with call to pending_diagnostic::same_tree_p.
+ * sm-malloc.cc (malloc_diagnostic::subclass_equal_p): Likewise.
+ (possible_null_arg::subclass_equal_p): Likewise.
+ (null_arg::subclass_equal_p): Likewise.
+ (free_of_non_heap::subclass_equal_p): Likewise.
+ * sm-pattern-test.cc (pattern_match::operator==): Likewise.
+ * sm-sensitive.cc (exposure_through_output_file::operator==):
+ Likewise.
+ * sm-taint.cc (tainted_array_index::operator==): Likewise.
+
+2020-01-14 David Malcolm <dmalcolm@redhat.com>
+
* diagnostic-manager.cc (dedupe_winners::add): Add logging
of deduplication decisions made.
diff --git a/gcc/analyzer/diagnostic-manager.cc b/gcc/analyzer/diagnostic-manager.cc
index 7bd21d6..ea2ff30 100644
--- a/gcc/analyzer/diagnostic-manager.cc
+++ b/gcc/analyzer/diagnostic-manager.cc
@@ -91,6 +91,20 @@ saved_diagnostic::~saved_diagnostic ()
delete m_d;
}
+bool
+saved_diagnostic::operator== (const saved_diagnostic &other) const
+{
+ return (m_sm == other.m_sm
+ /* We don't compare m_enode. */
+ && m_snode == other.m_snode
+ && m_stmt == other.m_stmt
+ /* We don't compare m_stmt_finder. */
+ && pending_diagnostic::same_tree_p (m_var, other.m_var)
+ && m_state == other.m_state
+ && m_d->equal_p (*other.m_d)
+ && m_trailing_eedge == other.m_trailing_eedge);
+}
+
/* class diagnostic_manager. */
/* diagnostic_manager's ctor. */
diff --git a/gcc/analyzer/diagnostic-manager.h b/gcc/analyzer/diagnostic-manager.h
index aa93943..c0f13bf 100644
--- a/gcc/analyzer/diagnostic-manager.h
+++ b/gcc/analyzer/diagnostic-manager.h
@@ -34,18 +34,7 @@ public:
pending_diagnostic *d);
~saved_diagnostic ();
- bool operator== (const saved_diagnostic &other) const
- {
- return (m_sm == other.m_sm
- /* We don't compare m_enode. */
- && m_snode == other.m_snode
- && m_stmt == other.m_stmt
- /* We don't compare m_stmt_finder. */
- && m_var == other.m_var
- && m_state == other.m_state
- && m_d->equal_p (*other.m_d)
- && m_trailing_eedge == other.m_trailing_eedge);
- }
+ bool operator== (const saved_diagnostic &other) const;
//private:
const state_machine *m_sm;
diff --git a/gcc/analyzer/pending-diagnostic.cc b/gcc/analyzer/pending-diagnostic.cc
index f6c4883..b692c98 100644
--- a/gcc/analyzer/pending-diagnostic.cc
+++ b/gcc/analyzer/pending-diagnostic.cc
@@ -67,4 +67,13 @@ evdesc::event_desc::formatted_print (const char *fmt, ...) const
return result;
}
+/* Return true if T1 and T2 are "the same" for the purposes of
+ diagnostic deduplication. */
+
+bool
+pending_diagnostic::same_tree_p (tree t1, tree t2)
+{
+ return simple_cst_equal (t1, t2) == 1;
+}
+
#endif /* #if ENABLE_ANALYZER */
diff --git a/gcc/analyzer/pending-diagnostic.h b/gcc/analyzer/pending-diagnostic.h
index bb03e75..6132fcf 100644
--- a/gcc/analyzer/pending-diagnostic.h
+++ b/gcc/analyzer/pending-diagnostic.h
@@ -169,6 +169,10 @@ class pending_diagnostic
below for a convenience subclass for implementing this. */
virtual bool subclass_equal_p (const pending_diagnostic &other) const = 0;
+ /* Return true if T1 and T2 are "the same" for the purposes of
+ diagnostic deduplication. */
+ static bool same_tree_p (tree t1, tree t2);
+
/* For greatest precision-of-wording, the various following "describe_*"
virtual functions give the pending diagnostic a way to describe events
in a diagnostic_path in terms that make sense for that diagnostic.
diff --git a/gcc/analyzer/sm-file.cc b/gcc/analyzer/sm-file.cc
index ba18bf7..375f522 100644
--- a/gcc/analyzer/sm-file.cc
+++ b/gcc/analyzer/sm-file.cc
@@ -96,7 +96,7 @@ public:
bool subclass_equal_p (const pending_diagnostic &base_other) const OVERRIDE
{
- return m_arg == ((const file_diagnostic &)base_other).m_arg;
+ return same_tree_p (m_arg, ((const file_diagnostic &)base_other).m_arg);
}
label_text describe_state_change (const evdesc::state_change &change)
diff --git a/gcc/analyzer/sm-malloc.cc b/gcc/analyzer/sm-malloc.cc
index 80ceb0f..15fa1c7 100644
--- a/gcc/analyzer/sm-malloc.cc
+++ b/gcc/analyzer/sm-malloc.cc
@@ -102,7 +102,7 @@ public:
bool subclass_equal_p (const pending_diagnostic &base_other) const OVERRIDE
{
- return m_arg == ((const malloc_diagnostic &)base_other).m_arg;
+ return same_tree_p (m_arg, ((const malloc_diagnostic &)base_other).m_arg);
}
label_text describe_state_change (const evdesc::state_change &change)
@@ -282,7 +282,7 @@ public:
{
const possible_null_arg &sub_other
= (const possible_null_arg &)base_other;
- return (m_arg == sub_other.m_arg
+ return (same_tree_p (m_arg, sub_other.m_arg)
&& m_fndecl == sub_other.m_fndecl
&& m_arg_idx == sub_other.m_arg_idx);
}
@@ -373,7 +373,7 @@ public:
{
const null_arg &sub_other
= (const null_arg &)base_other;
- return (m_arg == sub_other.m_arg
+ return (same_tree_p (m_arg, sub_other.m_arg)
&& m_fndecl == sub_other.m_fndecl
&& m_arg_idx == sub_other.m_arg_idx);
}
@@ -499,7 +499,7 @@ public:
FINAL OVERRIDE
{
const free_of_non_heap &other = (const free_of_non_heap &)base_other;
- return (m_arg == other.m_arg && m_kind == other.m_kind);
+ return (same_tree_p (m_arg, other.m_arg) && m_kind == other.m_kind);
}
bool emit (rich_location *rich_loc) FINAL OVERRIDE
diff --git a/gcc/analyzer/sm-pattern-test.cc b/gcc/analyzer/sm-pattern-test.cc
index 8c70858..571e13e 100644
--- a/gcc/analyzer/sm-pattern-test.cc
+++ b/gcc/analyzer/sm-pattern-test.cc
@@ -78,9 +78,9 @@ public:
bool operator== (const pattern_match &other) const
{
- return (m_lhs == other.m_lhs
+ return (same_tree_p (m_lhs, other.m_lhs)
&& m_op == other.m_op
- && m_rhs == other.m_rhs);
+ && same_tree_p (m_rhs, other.m_rhs));
}
bool emit (rich_location *rich_loc) FINAL OVERRIDE
diff --git a/gcc/analyzer/sm-sensitive.cc b/gcc/analyzer/sm-sensitive.cc
index efb2432..16b53e2 100644
--- a/gcc/analyzer/sm-sensitive.cc
+++ b/gcc/analyzer/sm-sensitive.cc
@@ -95,7 +95,7 @@ public:
bool operator== (const exposure_through_output_file &other) const
{
- return m_arg == other.m_arg;
+ return same_tree_p (m_arg, other.m_arg);
}
bool emit (rich_location *rich_loc) FINAL OVERRIDE
diff --git a/gcc/analyzer/sm-taint.cc b/gcc/analyzer/sm-taint.cc
index 9382853..e454407 100644
--- a/gcc/analyzer/sm-taint.cc
+++ b/gcc/analyzer/sm-taint.cc
@@ -100,7 +100,7 @@ public:
bool operator== (const tainted_array_index &other) const
{
- return m_arg == other.m_arg;
+ return same_tree_p (m_arg, other.m_arg);
}
bool emit (rich_location *rich_loc) FINAL OVERRIDE
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 8e99328..1cdaa810 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2020-01-14 David Malcolm <dmalcolm@redhat.com>
+
+ * gcc.dg/analyzer/CVE-2005-1689-dedupe-issue.c: New test.
+
2020-01-15 Jakub Jelinek <jakub@redhat.com>
PR lto/91576
diff --git a/gcc/testsuite/gcc.dg/analyzer/CVE-2005-1689-dedupe-issue.c b/gcc/testsuite/gcc.dg/analyzer/CVE-2005-1689-dedupe-issue.c
new file mode 100644
index 0000000..941d3b8
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/analyzer/CVE-2005-1689-dedupe-issue.c
@@ -0,0 +1,26 @@
+#include <stdlib.h>
+
+typedef struct _krb5_data {
+ char *data;
+} krb5_data;
+
+/* Ensure that we de-duplicate the various paths to reach here,
+ and only emit one diagnostic. */
+
+void
+recvauth_common(krb5_data inbuf)
+{
+ free(inbuf.data);
+ free(inbuf.data); /* { dg-warning "double-'free'" } */
+ /* { dg-message "2 duplicates" "" { target *-*-* } .-1 } */
+}
+
+void krb5_recvauth(krb5_data inbuf)
+{
+ recvauth_common(inbuf);
+}
+
+void krb5_recvauth_version(krb5_data inbuf)
+{
+ recvauth_common(inbuf);
+}
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