The s390-pci-bus.c code, Coverity complains about a possible overflow
because get_table_index() can return -1 if the ett value passed in is
not one of the three permitted ZPCI_ETT_PT, ZPCI_ETT_ST, ZPCI_ETT_RT,
but the caller in table_translate() doesn't check this and instead
uses the return value directly in a calculation of the guest address
to read from.
In fact this case cannot happen, because:
* get_table_index() is called only from table_translate()
* the only caller of table_translate() loops through the ett values
in the order RT, ST, PT until table_translate() returns 0
* table_translate() will return 0 for the error cases and when
translate_iscomplete() returns true
* translate_iscomplete() is always true for ZPCI_ETT_PT
So table_translate() is always called with a valid ett value.
Instead of having the various functions called from table_translate()
return a default or dummy value when the ett argument is out of range,
use g_assert_not_reached() to indicate that this is impossible.
Coverity: CID 1547609
Signed-off-by: Peter Maydell <peter.mayd...@linaro.org>
---
Disclaimer: only tested with 'make check/make check-functional'
hw/s390x/s390-pci-bus.c | 26 ++++++++++++++------------
1 file changed, 14 insertions(+), 12 deletions(-)
diff --git a/hw/s390x/s390-pci-bus.c b/hw/s390x/s390-pci-bus.c
index e6aa44531f6..f87d2748b63 100644
--- a/hw/s390x/s390-pci-bus.c
+++ b/hw/s390x/s390-pci-bus.c
@@ -384,9 +384,9 @@ static uint64_t get_table_index(uint64_t iova, int8_t ett)
return calc_sx(iova);
case ZPCI_ETT_RT:
return calc_rtx(iova);
+ default:
+ g_assert_not_reached();
}
-
- return -1;
}
static bool entry_isvalid(uint64_t entry, int8_t ett)
@@ -397,22 +397,24 @@ static bool entry_isvalid(uint64_t entry, int8_t ett)
case ZPCI_ETT_ST:
case ZPCI_ETT_RT:
return rt_entry_isvalid(entry);
+ default:
+ g_assert_not_reached();
}
-
- return false;
}
/* Return true if address translation is done */
static bool translate_iscomplete(uint64_t entry, int8_t ett)
{
switch (ett) {
- case 0:
+ case ZPCI_ETT_ST:
return (entry & ZPCI_TABLE_FC) ? true : false;
- case 1:
+ case ZPCI_ETT_RT:
return false;
+ case ZPCI_ETT_PT:
+ return true;
+ default:
+ g_assert_not_reached();
}
-
- return true;
}
static uint64_t get_frame_size(int8_t ett)
@@ -424,9 +426,9 @@ static uint64_t get_frame_size(int8_t ett)
return 1ULL << 20;
case ZPCI_ETT_RT:
return 1ULL << 31;
+ default:
+ g_assert_not_reached();
}
-
- return 0;
}
static uint64_t get_next_table_origin(uint64_t entry, int8_t ett)
@@ -438,9 +440,9 @@ static uint64_t get_next_table_origin(uint64_t entry,
int8_t ett)
return get_st_pto(entry);
case ZPCI_ETT_RT:
return get_rt_sto(entry);
+ default:
+ g_assert_not_reached();
}
-
- return 0;
}
/**
--
2.43.0
