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mm-modem-helpers-telit: fix undefined bitshifts

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Since this plugin uses a bitmask to represent bands, we have
to be wary of shifting outside the precision of the bitmask
storage type. In this case, it was possible to generate 1 << 31
in a signed integer type as an intermediate step of B3G_FLAG,
which is undefined behavior (and usually results in INT_MIN,
breaking comparisons with the value).

Bug was reported to the chromium tracker at crbug.com/1019301

Original patch updated by Aleksander Morgado to leave
MM_MODEM_BAND_TELIT_3G_LAST as MM_MODEM_BAND_UTRAN_19, as that is the
highest 3G band supported by the current implementation. Worth noting
that this was not a real bug as the maximum flag we would have been
setting was (1 << 19) anyway.
This commit is contained in:
Eric Caruso
2019-10-29 12:19:22 -07:00
committed by Aleksander Morgado
parent e0f0d62369
commit c79d945073
1 changed files with 8 additions and 7 deletions
Download Patch File Download Diff File Expand all files Collapse all files

15
plugins/telit/mm-modem-helpers-telit.c
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@@ -83,7 +83,7 @@ static const guint band_utran_index[] = {
#define MM_MODEM_BAND_TELIT_3G_LAST MM_MODEM_BAND_UTRAN_19
#define B3G_NUM(band) band_utran_index[band]
#define B3G_FLAG(band) ((B3G_NUM (band) > 0) ? (1 << (B3G_NUM (band) - B3G_NUM (MM_MODEM_BAND_TELIT_3G_FIRST))) : 0)
#define B3G_FLAG(band) ((B3G_NUM (band) > 0) ? (1LL << (B3G_NUM (band) - B3G_NUM (MM_MODEM_BAND_TELIT_3G_FIRST))) : 0)
/* Index of the arrays is the telit 3G band value.
* The bitmask value here is built from the 3G MMModemBand values right away.
@@ -93,10 +93,10 @@ static const guint band_utran_index[] = {
*/
#define TELIT_3G_TO_MM_BAND_MASK_DEFAULT_N_ELEMENTS 27
static guint32 telit_3g_to_mm_band_mask_default[TELIT_3G_TO_MM_BAND_MASK_DEFAULT_N_ELEMENTS];
static guint64 telit_3g_to_mm_band_mask_default[TELIT_3G_TO_MM_BAND_MASK_DEFAULT_N_ELEMENTS];
#define TELIT_3G_TO_MM_BAND_MASK_ALTERNATE_N_ELEMENTS 20
static guint32 telit_3g_to_mm_band_mask_alternate[TELIT_3G_TO_MM_BAND_MASK_ALTERNATE_N_ELEMENTS];
static guint64 telit_3g_to_mm_band_mask_alternate[TELIT_3G_TO_MM_BAND_MASK_ALTERNATE_N_ELEMENTS];
static void
initialize_telit_3g_to_mm_band_masks (void)
@@ -198,14 +198,14 @@ mm_telit_build_bnd_request (GArray *bands_array,
GError **error)
{
guint32 mask2g = 0;
guint32 mask3g = 0;
guint64 mask3g = 0;
guint64 mask4g = 0;
guint i;
gint flag2g = -1;
gint flag3g = -1;
gint flag4g = -1;
gchar *cmd;
const guint32 *telit_3g_to_mm_band_mask;
const guint64 *telit_3g_to_mm_band_mask;
guint telit_3g_to_mm_band_mask_n_elements;
initialize_telit_3g_to_mm_band_masks ();
@@ -229,7 +229,8 @@ mm_telit_build_bnd_request (GArray *bands_array,
(band >= MM_MODEM_BAND_TELIT_2G_FIRST) && (band <= MM_MODEM_BAND_TELIT_2G_LAST))
mask2g += B2G_FLAG (band);
/* Convert 3G bands into a bitmask, to match against telit_3g_to_mm_band_mask. */
/* Convert 3G bands into a bitmask, to match against telit_3g_to_mm_band_mask. We use
* a 64-bit explicit bitmask so that all values fit correctly. */
if (flag3g && mm_common_band_is_utran (band) &&
(B3G_NUM (band) >= B3G_NUM (MM_MODEM_BAND_TELIT_3G_FIRST)) && (B3G_NUM (band) <= B3G_NUM (MM_MODEM_BAND_TELIT_3G_LAST)))
mask3g += B3G_FLAG (band);
@@ -429,7 +430,7 @@ telit_get_3g_mm_bands (GMatchInfo *match_info,
GArray *values = NULL;
gchar *match_str = NULL;
guint i;
const guint32 *telit_3g_to_mm_band_mask;
const guint64 *telit_3g_to_mm_band_mask;
guint telit_3g_to_mm_band_mask_n_elements;
initialize_telit_3g_to_mm_band_masks ();