Change in flashrom[master]: dummyflasher.c: Fix data leak in params processing error paths

[Nico Huber (Code Review)]

Nico Huber has submitted this change. ( https://review.coreboot.org/c/flashrom/+/54748 )

Change subject: dummyflasher.c: Fix data leak in params processing error paths
......................................................................

dummyflasher.c: Fix data leak in params processing error paths

This patch extracts params processing into a separate function. Now
all error paths of params processing return 1 back to init function
which frees data.

And there was just one more error path in init function where
free(data) needed to be added.

This is a follow up on commit 3b8fe0f8e907c0ba9f7c7935e950f3e1538d427f
which moves global state into spi_master data.

A good side-effect of the change is: init function becomes easier
to read.

BUG=b:185191942
TEST=ninja test

Change-Id: I04f55f77bb4703f1d88b2191c45a22be3c97bf87
Signed-off-by: Anastasia Klimchuk 
Reviewed-on: https://review.coreboot.org/c/flashrom/+/54748
Tested-by: build bot (Jenkins) 
Reviewed-by: Nico Huber 
---
M dummyflasher.c
1 file changed, 51 insertions(+), 27 deletions(-)

Approvals:
  build bot (Jenkins): Verified
  Nico Huber: Looks good to me, approved

diff --git a/dummyflasher.c b/dummyflasher.c
index dcf97b5..e2f38f5 100644
--- a/dummyflasher.c
+++ b/dummyflasher.c
@@ -643,30 +643,17 @@
    return 0;
 }

-int dummy_init(void)
+static int init_data(struct emu_data *data, enum chipbustype *dummy_buses_supported)
 {
+
    char *bustext = NULL;
    char *tmp = NULL;
    unsigned int i;
+	char *endptr;
 #if EMULATE_SPI_CHIP
    char *status = NULL;
    int size = -1;  /* size for VARIABLE_SIZE chip device */
 #endif
-#if EMULATE_CHIP
-	struct stat image_stat;
-#endif
-	char *endptr;
-
-	struct emu_data *data = calloc(1, sizeof(struct emu_data));
-	if (!data) {
-		msg_perr("Out of memory!\n");
-		return 1;
-	}
-	data->emu_chip = EMULATE_NONE;
-	data->delay_us = 0;
-	data->spi_write_256_chunksize = 256;
-
-	msg_pspew("%s\n", __func__);

bustext = extract_programmer_param("bus");
    msg_pdbg("Requested buses are: %s\n", bustext ? bustext : "default");
@@ -675,24 +662,24 @@
    /* Convert the parameters to lowercase. */
    tolower_string(bustext);

-	enum chipbustype dummy_buses_supported = BUS_NONE;
+	*dummy_buses_supported = BUS_NONE;
    if (strstr(bustext, "parallel")) {
-		dummy_buses_supported |= BUS_PARALLEL;
+		*dummy_buses_supported |= BUS_PARALLEL;
    	msg_pdbg("Enabling support for %s flash.\n", "parallel");
    }
    if (strstr(bustext, "lpc")) {
-		dummy_buses_supported |= BUS_LPC;
+		*dummy_buses_supported |= BUS_LPC;
    	msg_pdbg("Enabling support for %s flash.\n", "LPC");
    }
    if (strstr(bustext, "fwh")) {
-		dummy_buses_supported |= BUS_FWH;
+		*dummy_buses_supported |= BUS_FWH;
    	msg_pdbg("Enabling support for %s flash.\n", "FWH");
    }
    if (strstr(bustext, "spi")) {
-		dummy_buses_supported |= BUS_SPI;
+		*dummy_buses_supported |= BUS_SPI;
    	msg_pdbg("Enabling support for %s flash.\n", "SPI");
    }
-	if (dummy_buses_supported == BUS_NONE)
+	if (*dummy_buses_supported == BUS_NONE)
    	msg_pdbg("Support for all flash bus types disabled.\n");
    free(bustext);

@@ -838,14 +825,15 @@
    	}
    	free(tmp);
    }
-#endif
+#endif /* EMULATE_SPI_CHIP */

tmp = extract_programmer_param("emulate");
    if (!tmp) {
    	msg_pdbg("Not emulating any flash chip.\n");
    	/* Nothing else to do. */
-		goto dummy_init_out;
+		return 0;
    }
+
 #if EMULATE_SPI_CHIP
    if (!strcmp(tmp, "M25P10.RES")) {
    	data->emu_chip = EMULATE_ST_M25P10_RES;
@@ -933,7 +921,7 @@
    	msg_pdbg("Emulating generic SPI flash chip (size=%d bytes)\n",
    	         data->emu_chip_size);
    }
-#endif
+#endif /* EMULATE_SPI_CHIP */
    if (data->emu_chip == EMULATE_NONE) {
    	msg_perr("Invalid chip specified for emulation: %s\n", tmp);
    	free(tmp);
@@ -972,7 +960,7 @@
    	msg_pdbg("Initial status register is set to 0x%02x.\n",
    		 data->emu_status);
    }
-#endif
+#endif /* EMULATE_SPI_CHIP */

data->flashchip_contents = malloc(data->emu_chip_size);
    if (!data->flashchip_contents) {
@@ -980,6 +968,41 @@
    	return 1;
    }

+#endif /* EMULATE_CHIP */
+
+	return 0;
+}
+
+int dummy_init(void)
+{
+#if EMULATE_CHIP
+	struct stat image_stat;
+#endif
+
+	struct emu_data *data = calloc(1, sizeof(struct emu_data));
+	if (!data) {
+		msg_perr("Out of memory!\n");
+		return 1;
+	}
+	data->emu_chip = EMULATE_NONE;
+	data->delay_us = 0;
+	data->spi_write_256_chunksize = 256;
+
+	msg_pspew("%s\n", __func__);
+
+	enum chipbustype dummy_buses_supported;
+	if (init_data(data, &dummy_buses_supported)) {
+		free(data);
+		return 1;
+	}
+
+#if EMULATE_CHIP
+	if (data->emu_chip == EMULATE_NONE) {
+		msg_pdbg("Not emulating any flash chip.\n");
+		/* Nothing else to do. */
+		goto dummy_init_out;
+	}
+
    msg_pdbg("Filling fake flash chip with 0x%02x, size %i\n",
    		data->erase_to_zero ? 0x00 : 0xff, data->emu_chip_size);
    memset(data->flashchip_contents, data->erase_to_zero ? 0x00 : 0xff, data->emu_chip_size);
@@ -1003,13 +1026,14 @@
    			msg_perr("Unable to read %s\n", data->emu_persistent_image);
    			free(data->emu_persistent_image);
    			free(data->flashchip_contents);
+				free(data);
    			return 1;
    		}
    	} else {
    		msg_pdbg("doesn't match.\n");
    	}
    }
-#endif
+#endif /* EMULATE_CHIP */

dummy_init_out:
    if (register_shutdown(dummy_shutdown, data)) {