| Message ID | 20240705-bnxt-str-v1-2-bafc769ed89e@kernel.org (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | bnxt_en: address string truncation | expand |
On Fri, Jul 5, 2024 at 4:27 AM Simon Horman <horms@kernel.org> wrote: > diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c > index 220d05e2f6fa..15e68c8e599d 100644 > --- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c > +++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c > @@ -10538,7 +10538,7 @@ static int bnxt_trim_rings(struct bnxt *bp, int *rx, int *tx, int max, > return __bnxt_trim_rings(bp, rx, tx, max, sh); > } > > -static void bnxt_setup_msix(struct bnxt *bp) > +static int bnxt_setup_msix(struct bnxt *bp) > { > const int len = sizeof(bp->irq_tbl[0].name); > struct net_device *dev = bp->dev; > @@ -10558,6 +10558,7 @@ static void bnxt_setup_msix(struct bnxt *bp) > for (i = 0; i < bp->cp_nr_rings; i++) { > int map_idx = bnxt_cp_num_to_irq_num(bp, i); > char *attr; > + int rc; > > if (bp->flags & BNXT_FLAG_SHARED_RINGS) > attr = "TxRx"; > @@ -10566,24 +10567,35 @@ static void bnxt_setup_msix(struct bnxt *bp) > else > attr = "tx"; > > - snprintf(bp->irq_tbl[map_idx].name, len, "%s-%s-%d", dev->name, > - attr, i); > + rc = snprintf(bp->irq_tbl[map_idx].name, len, "%s-%s-%d", > + dev->name, attr, i); > + if (rc >= len) > + return -E2BIG; I may be missing something obvious here. snprintf() will truncate and not overwrite the buffer, right? Why is it necessary to abort if there is truncation? Thanks.
On Fri, Jul 05, 2024 at 11:27:47AM -0700, Michael Chan wrote: > On Fri, Jul 5, 2024 at 4:27 AM Simon Horman <horms@kernel.org> wrote: > > diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c > > index 220d05e2f6fa..15e68c8e599d 100644 > > --- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c > > +++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c > > @@ -10538,7 +10538,7 @@ static int bnxt_trim_rings(struct bnxt *bp, int *rx, int *tx, int max, > > return __bnxt_trim_rings(bp, rx, tx, max, sh); > > } > > > > -static void bnxt_setup_msix(struct bnxt *bp) > > +static int bnxt_setup_msix(struct bnxt *bp) > > { > > const int len = sizeof(bp->irq_tbl[0].name); > > struct net_device *dev = bp->dev; > > @@ -10558,6 +10558,7 @@ static void bnxt_setup_msix(struct bnxt *bp) > > for (i = 0; i < bp->cp_nr_rings; i++) { > > int map_idx = bnxt_cp_num_to_irq_num(bp, i); > > char *attr; > > + int rc; > > > > if (bp->flags & BNXT_FLAG_SHARED_RINGS) > > attr = "TxRx"; > > @@ -10566,24 +10567,35 @@ static void bnxt_setup_msix(struct bnxt *bp) > > else > > attr = "tx"; > > > > - snprintf(bp->irq_tbl[map_idx].name, len, "%s-%s-%d", dev->name, > > - attr, i); > > + rc = snprintf(bp->irq_tbl[map_idx].name, len, "%s-%s-%d", > > + dev->name, attr, i); > > + if (rc >= len) > > + return -E2BIG; > > I may be missing something obvious here. snprintf() will truncate and > not overwrite the buffer, right? Why is it necessary to abort if > there is truncation? Thanks. The (incorrect) assumption on my side was that truncated names are undesirable and should be treated as an error case. Sorry for not making that clearer.
diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c index 220d05e2f6fa..15e68c8e599d 100644 --- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c +++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c @@ -10538,7 +10538,7 @@ static int bnxt_trim_rings(struct bnxt *bp, int *rx, int *tx, int max, return __bnxt_trim_rings(bp, rx, tx, max, sh); } -static void bnxt_setup_msix(struct bnxt *bp) +static int bnxt_setup_msix(struct bnxt *bp) { const int len = sizeof(bp->irq_tbl[0].name); struct net_device *dev = bp->dev; @@ -10558,6 +10558,7 @@ static void bnxt_setup_msix(struct bnxt *bp) for (i = 0; i < bp->cp_nr_rings; i++) { int map_idx = bnxt_cp_num_to_irq_num(bp, i); char *attr; + int rc; if (bp->flags & BNXT_FLAG_SHARED_RINGS) attr = "TxRx"; @@ -10566,24 +10567,35 @@ static void bnxt_setup_msix(struct bnxt *bp) else attr = "tx"; - snprintf(bp->irq_tbl[map_idx].name, len, "%s-%s-%d", dev->name, - attr, i); + rc = snprintf(bp->irq_tbl[map_idx].name, len, "%s-%s-%d", + dev->name, attr, i); + if (rc >= len) + return -E2BIG; bp->irq_tbl[map_idx].handler = bnxt_msix; } + + return 0; } -static void bnxt_setup_inta(struct bnxt *bp) +static int bnxt_setup_inta(struct bnxt *bp) { const int len = sizeof(bp->irq_tbl[0].name); + int rc; + if (bp->num_tc) { netdev_reset_tc(bp->dev); bp->num_tc = 0; } - snprintf(bp->irq_tbl[0].name, len, "%s-%s-%d", bp->dev->name, "TxRx", - 0); + rc = snprintf(bp->irq_tbl[0].name, len, "%s-%s-%d", bp->dev->name, + "TxRx", 0); + if (rc >= len) + return -E2BIG; + bp->irq_tbl[0].handler = bnxt_inta; + + return 0; } static int bnxt_init_int_mode(struct bnxt *bp); @@ -10599,9 +10611,11 @@ static int bnxt_setup_int_mode(struct bnxt *bp) } if (bp->flags & BNXT_FLAG_USING_MSIX) - bnxt_setup_msix(bp); + rc = bnxt_setup_msix(bp); else - bnxt_setup_inta(bp); + rc = bnxt_setup_inta(bp); + if (rc) + return rc; rc = bnxt_set_real_num_queues(bp); return rc;
Given the sizes of the buffers involved, it is theoretically possible for irq names to be truncated. Detect this and propagate an error if this occurs. Flagged by gcc-14: .../bnxt.c: In function 'bnxt_setup_int_mode': .../bnxt.c:10584:48: warning: '%s' directive output may be truncated writing 4 bytes into a region of size between 2 and 17 [-Wformat-truncation=] 10584 | snprintf(bp->irq_tbl[0].name, len, "%s-%s-%d", bp->dev->name, "TxRx", | ^~ ~~~~~~ In function 'bnxt_setup_inta', inlined from 'bnxt_setup_int_mode' at .../bnxt.c:10604:3: .../bnxt.c:10584:9: note: 'snprintf' output between 8 and 23 bytes into a destination of size 18 10584 | snprintf(bp->irq_tbl[0].name, len, "%s-%s-%d", bp->dev->name, "TxRx", | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 10585 | 0); | ~~ .../bnxt.c: In function 'bnxt_setup_int_mode': .../bnxt.c:10569:62: warning: '%s' directive output may be truncated writing between 2 and 4 bytes into a region of size between 2 and 17 [-Wformat-truncation=] 10569 | snprintf(bp->irq_tbl[map_idx].name, len, "%s-%s-%d", dev->name, | ^~ In function 'bnxt_setup_msix', inlined from 'bnxt_setup_int_mode' at .../bnxt.c:10602:3: .../bnxt.c:10569:58: note: directive argument in the range [-2147483643, 2147483646] 10569 | snprintf(bp->irq_tbl[map_idx].name, len, "%s-%s-%d", dev->name, | ^~~~~~~~~~ .../bnxt.c:10569:17: note: 'snprintf' output between 6 and 33 bytes into a destination of size 18 10569 | snprintf(bp->irq_tbl[map_idx].name, len, "%s-%s-%d", dev->name, | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 10570 | attr, i); | ~~~~~~~~ Compile tested only. Signed-off-by: Simon Horman <horms@kernel.org> --- drivers/net/ethernet/broadcom/bnxt/bnxt.c | 30 ++++++++++++++++++++++-------- 1 file changed, 22 insertions(+), 8 deletions(-)