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fuzz: Expect the cmdline in a freeable GString

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In the initial FuzzTarget, get_init_cmdline returned a char *. With this
API, we had no guarantee about where the string came from. For example,
i440fx-qtest-reboot-fuzz simply returned a pointer to a string literal,
while the QOS-based targets build the arguments out in a GString an
return the gchar *str pointer. Since we did not try to free the cmdline,
we have a leak for any targets that do not simply return string
literals. Clean up this mess by forcing fuzz-targets to return
a GString, that we can free.

Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Message-Id: <20200714174616.20709-1-alxndr@bu.edu>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
This commit is contained in:
Alexander Bulekov 2020-07-14 13:46:16 -04:00 committed by Thomas Huth
parent 15c51f724e
commit f5ec79f5e0
4 changed files with 14 additions and 15 deletions
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13
tests/qtest/fuzz/fuzz.c
View File

@ -199,16 +199,15 @@ int LLVMFuzzerInitialize(int *argc, char ***argv, char ***envp)
}
/* Run QEMU's softmmu main with the fuzz-target dependent arguments */
const char *init_cmdline = fuzz_target->get_init_cmdline(fuzz_target);
init_cmdline = g_strdup_printf("%s -qtest /dev/null -qtest-log %s",
init_cmdline,
getenv("QTEST_LOG") ? "/dev/fd/2"
: "/dev/null");
GString *cmd_line = fuzz_target->get_init_cmdline(fuzz_target);
g_string_append_printf(cmd_line,
" -qtest /dev/null -qtest-log %s",
getenv("QTEST_LOG") ? "/dev/fd/2" : "/dev/null");
/* Split the runcmd into an argv and argc */
wordexp_t result;
wordexp(init_cmdline, &result, 0);
wordexp(cmd_line->str, &result, 0);
g_string_free(cmd_line, true);
qemu_init(result.we_wordc, result.we_wordv, NULL);

6
tests/qtest/fuzz/fuzz.h
View File

@ -50,10 +50,10 @@ typedef struct FuzzTarget {
/*
* returns the arg-list that is passed to qemu/softmmu init()
* Cannot be NULL
* Returns the arguments that are passed to qemu/softmmu init(). Freed by
* the caller.
*/
const char* (*get_init_cmdline)(struct FuzzTarget *);
GString *(*get_init_cmdline)(struct FuzzTarget *);
/*
* will run once, prior to running qemu/softmmu init.

4
tests/qtest/fuzz/i440fx_fuzz.c
View File

@ -158,9 +158,9 @@ static void i440fx_fuzz_qos_fork(QTestState *s,
static const char *i440fx_qtest_argv = TARGET_NAME " -machine accel=qtest"
" -m 0 -display none";
static const char *i440fx_argv(FuzzTarget *t)
static GString *i440fx_argv(FuzzTarget *t)
{
return i440fx_qtest_argv;
return g_string_new(i440fx_qtest_argv);
}
static void fork_init(void)

6
tests/qtest/fuzz/qos_fuzz.c
View File

@ -66,7 +66,7 @@ void *qos_allocate_objects(QTestState *qts, QGuestAllocator **p_alloc)
return allocate_objects(qts, current_path + 1, p_alloc);
}
static const char *qos_build_main_args(void)
static GString *qos_build_main_args(void)
{
char **path = fuzz_path_vec;
QOSGraphNode *test_node;
@ -88,7 +88,7 @@ static const char *qos_build_main_args(void)
/* Prepend the arguments that we need */
g_string_prepend(cmd_line,
TARGET_NAME " -display none -machine accel=qtest -m 64 ");
return cmd_line->str;
return cmd_line;
}
/*
@ -189,7 +189,7 @@ static void walk_path(QOSGraphNode *orig_path, int len)
g_free(path_str);
}
static const char *qos_get_cmdline(FuzzTarget *t)
static GString *qos_get_cmdline(FuzzTarget *t)
{
/*
* Set a global variable that we use to identify the qos_path for our