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From: Paolo Bonzini <pbonzini@redhat.com>
To: qemu-devel@nongnu.org
Subject: [PULL 8/8] coverity-model: write models fully for non-array allocation functions
Date: Mon,  2 Aug 2021 18:15:42 +0200	[thread overview]
Message-ID: <20210802161542.381976-9-pbonzini@redhat.com> (raw)
In-Reply-To: <20210802161542.381976-1-pbonzini@redhat.com>

Coverity seems to have issues figuring out the properties of g_malloc0
and other non *_n functions.  While this was "fixed" by removing the
custom second argument to __coverity_mark_as_afm_allocated__, inline
the code from the array-based allocation functions to avoid future
issues.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 scripts/coverity-scan/model.c | 57 +++++++++++++++++++++++++++++++----
 1 file changed, 51 insertions(+), 6 deletions(-)

diff --git a/scripts/coverity-scan/model.c b/scripts/coverity-scan/model.c
index 028f13e9e3..9d4fba53d9 100644
--- a/scripts/coverity-scan/model.c
+++ b/scripts/coverity-scan/model.c
@@ -269,32 +269,77 @@ void *g_try_realloc_n(void *ptr, size_t nmemb, size_t size)
 
 void *g_malloc(size_t size)
 {
-    return g_malloc_n(1, size);
+    void *ptr;
+
+    __coverity_negative_sink__(size);
+    ptr = __coverity_alloc__(size);
+    if (!ptr) {
+        __coverity_panic__();
+    }
+    __coverity_mark_as_uninitialized_buffer__(ptr);
+    __coverity_mark_as_afm_allocated__(ptr, AFM_free);
+    return ptr;
 }
 
 void *g_malloc0(size_t size)
 {
-    return g_malloc0_n(1, size);
+    void *ptr;
+
+    __coverity_negative_sink__(size);
+    ptr = __coverity_alloc__(size);
+    if (!ptr) {
+        __coverity_panic__();
+    }
+    __coverity_writeall0__(ptr);
+    __coverity_mark_as_afm_allocated__(ptr, AFM_free);
+    return ptr;
 }
 
 void *g_realloc(void *ptr, size_t size)
 {
-    return g_realloc_n(ptr, 1, size);
+    __coverity_negative_sink__(size);
+    __coverity_escape__(ptr);
+    ptr = __coverity_alloc__(size);
+    if (!ptr) {
+        __coverity_panic__();
+    }
+    /*
+     * Memory beyond the old size isn't actually initialized.  Can't
+     * model that.  See Coverity's realloc() model
+     */
+    __coverity_writeall__(ptr);
+    __coverity_mark_as_afm_allocated__(ptr, AFM_free);
+    return ptr;
 }
 
 void *g_try_malloc(size_t size)
 {
-    return g_try_malloc_n(1, size);
+    int nomem;
+
+    if (nomem) {
+        return NULL;
+    }
+    return g_malloc(size);
 }
 
 void *g_try_malloc0(size_t size)
 {
-    return g_try_malloc0_n(1, size);
+    int nomem;
+
+    if (nomem) {
+        return NULL;
+    }
+    return g_malloc0(size);
 }
 
 void *g_try_realloc(void *ptr, size_t size)
 {
-    return g_try_realloc_n(ptr, 1, size);
+    int nomem;
+
+    if (nomem) {
+        return NULL;
+    }
+    return g_realloc(ptr, size);
 }
 
 /* Other glib functions */
-- 
2.31.1



  parent reply	other threads:[~2021-08-02 16:21 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-02 16:15 [PULL 0/8] vl.c, coverity patches for QEMU 6.1-rc2 Paolo Bonzini
2021-08-02 16:15 ` [PULL 1/8] vl: introduce machine_merge_property Paolo Bonzini
2021-08-02 16:15 ` [PULL 2/8] vl: stop recording -smp in QemuOpts Paolo Bonzini
2021-08-02 16:15 ` [PULL 3/8] coverity-model: update address_space_read/write models Paolo Bonzini
2021-08-02 16:15 ` [PULL 4/8] coverity-model: make g_free a synonym of free Paolo Bonzini
2021-08-02 16:15 ` [PULL 5/8] coverity-model: remove model for more allocation functions Paolo Bonzini
2021-08-02 16:15 ` [PULL 6/8] coverity-model: clean up the models for array " Paolo Bonzini
2021-08-02 16:15 ` [PULL 7/8] coverity-model: constrain g_malloc/g_malloc0/g_realloc as never returning NULL Paolo Bonzini
2021-08-02 16:15 ` Paolo Bonzini [this message]
2021-08-02 19:12 ` [PULL 0/8] vl.c, coverity patches for QEMU 6.1-rc2 Peter Maydell

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