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In the Linux kernel, the following vulnerability has been resolved: bnx2x: Fix multiple UBSAN array-index-out-of-bounds Fix UBSAN warnings that occur when using a system with 32 physical cpu cores or more, or when the user defines a number of Ethernet queues greater than or equal to FP_SB_MAX_E1x using the num_queues module parameter. Currently there is a read/write out of bounds that occurs on the array "struct stats_query_entry query" present inside the "bnx2x_fw_stats_req" struct in "drivers/net/ethernet/broadcom/bnx2x/bnx2x.h". Looking at the definition of the "struct stats_query_entry query" array: struct stats_query_entry query[FP_SB_MAX_E1x+ BNX2X_FIRST_QUEUE_QUERY_IDX]; FP_SB_MAX_E1x is defined as the maximum number of fast path interrupts and has a value of 16, while BNX2X_FIRST_QUEUE_QUERY_IDX has a value of 3 meaning the array has a total size of 19. Since accesses to "struct stats_query_entry query" are offset-ted by BNX2X_FIRST_QUEUE_QUERY_IDX, that means that the total number of Ethernet queues should not exceed FP_SB_MAX_E1x (16). However one of these queues is reserved for FCOE and thus the number of Ethernet queues should be set to [FP_SB_MAX_E1x -1] (15) if FCOE is enabled or [FP_SB_MAX_E1x] (16) if it is not. This is also described in a comment in the source code in drivers/net/ethernet/broadcom/bnx2x/bnx2x.h just above the Macro definition of FP_SB_MAX_E1x. Below is the part of this explanation that it important for this patch /* * The total number of L2 queues, MSIX vectors and HW contexts (CIDs) is * control by the number of fast-path status blocks supported by the * device (HW/FW). Each fast-path status block (FP-SB) aka non-default * status block represents an independent interrupts context that can * serve a regular L2 networking queue. However special L2 queues such * as the FCoE queue do not require a FP-SB and other components like * the CNIC may consume FP-SB reducing the number of possible L2 queues * * If the maximum number of FP-SB available is X then: * a. If CNIC is supported it consumes 1 FP-SB thus the max number of * regular L2 queues is Y=X-1 * b. In MF mode the actual number of L2 queues is Y= (X-1/MF_factor) * c. If the FCoE L2 queue is supported the actual number of L2 queues * is Y+1 * d. The number of irqs (MSIX vectors) is either Y+1 (one extra for * slow-path interrupts) or Y+2 if CNIC is supported (one additional * FP interrupt context for the CNIC). * e. The number of HW context (CID count) is always X or X+1 if FCoE * L2 queue is supported. The cid for the FCoE L2 queue is always X. */ However this driver also supports NICs that use the E2 controller which can handle more queues due to having more FP-SB represented by FP_SB_MAX_E2. Looking at the commits when the E2 support was added, it was originally using the E1x parameters: commit f2e0899f0f27 ("bnx2x: Add 57712 support"). Back then FP_SB_MAX_E2 was set to 16 the same as E1x. However the driver was later updated to take full advantage of the E2 instead of having it be limited to the capabilities of the E1x. But as far as we can tell, the array "stats_query_entry query" was still limited to using the FP-SB available to the E1x cards as part of an oversignt when the driver was updated to take full advantage of the E2, and now with the driver being aware of the greater queue size supported by E2 NICs, it causes the UBSAN warnings seen in the stack traces below. This patch increases the size of the "stats_query_entry query" array by replacing FP_SB_MAX_E1x with FP_SB_MAX_E2 to be large enough to handle both types of NICs. Stack traces: UBSAN: array-index-out-of-bounds in drivers/net/ethernet/broadcom/bnx2x/bnx2x_stats.c:1529:11 index 20 is out of range for type 'stats_query_entry [19]' CPU: 12 PID: 858 Comm: systemd-network Not tainted 6.9.0-060900rc7-generic #202405052133 Hardware name: HP ProLiant DL360 Gen9/ProLiant DL360 ---truncated---
CVSS 3.1 Base Score 7.8. CVSS Attack Vector: local. CVSS Attack Complexity: low. CVSS Vector: (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).
In the code snippet below, an untrusted integer value is used to reference an object in an array.
}return array[index];If index is outside of the range of the array, this may result in an ArrayIndexOutOfBounds Exception being raised.
The following example takes a user-supplied value to allocate an array of objects and then operates on the array.
}list[0] = new Widget();die("Negative value supplied for list size, die evil hacker!");This example attempts to build a list from a user-specified value, and even checks to ensure a non-negative value is supplied. If, however, a 0 value is provided, the code will build an array of size 0 and then try to store a new Widget in the first location, causing an exception to be thrown.
In the following code, the method retrieves a value from an array at a specific array index location that is given as an input parameter to the method
}
return value;// check that the array index is less than the maximum// length of the array
value = array[index];// get the value at the specified index of the array// if array index is invalid then output error message// and return value indicating errorvalue = -1;However, this method only verifies that the given array index is less than the maximum length of the array but does not check for the minimum value (CWE-839). This will allow a negative value to be accepted as the input array index, which will result in a out of bounds read (CWE-125) and may allow access to sensitive memory. The input array index should be checked to verify that is within the maximum and minimum range required for the array (CWE-129). In this example the if statement should be modified to include a minimum range check, as shown below.
...// check that the array index is within the correct// range of values for the arrayThe following example retrieves the sizes of messages for a pop3 mail server. The message sizes are retrieved from a socket that returns in a buffer the message number and the message size, the message number (num) and size (size) are extracted from the buffer and the message size is placed into an array using the message number for the array index.
}/* capture the sizes of all messages */
// read values from socket and added to sizes array
// continue read from socket until buf only contains '.'break;sizes[num - 1] = size;...In this example the message number retrieved from the buffer could be a value that is outside the allowable range of indices for the array and could possibly be a negative number. Without proper validation of the value to be used for the array index an array overflow could occur and could potentially lead to unauthorized access to memory addresses and system crashes. The value of the array index should be validated to ensure that it is within the allowable range of indices for the array as in the following code.
}/* capture the sizes of all messages */
// read values from socket and added to sizes array
}// continue read from socket until buf only contains '.'break;
sizes[num - 1] = size;
report(stderr, "Warning: ignoring bogus data for message sizes returned by server.\n");/* warn about possible attempt to induce buffer overflow */...In the following example the method displayProductSummary is called from a Web service servlet to retrieve product summary information for display to the user. The servlet obtains the integer value of the product number from the user and passes it to the displayProductSummary method. The displayProductSummary method passes the integer value of the product number to the getProductSummary method which obtains the product summary from the array object containing the project summaries using the integer value of the product number as the array index.
}// Method called from servlet to obtain product information
return productSummary;String productSummary = getProductSummary(index);return products[index];In this example the integer value used as the array index that is provided by the user may be outside the allowable range of indices for the array which may provide unexpected results or cause the application to fail. The integer value used for the array index should be validated to ensure that it is within the allowable range of indices for the array as in the following code.
}// Method called from servlet to obtain product information
return productSummary;String productSummary = getProductSummary(index);
return productSummary;productSummary = products[index];throw new IndexOutOfBoundsException();An alternative in Java would be to use one of the collection objects such as ArrayList that will automatically generate an exception if an attempt is made to access an array index that is out of bounds.
} catch (IndexOutOfBoundsException ex) {...}productSummary = (String) productArray.get(index);The following example asks a user for an offset into an array to select an item.
}printf("You selected %s\n", items[index-1]);The programmer allows the user to specify which element in the list to select, however an attacker can provide an out-of-bounds offset, resulting in a buffer over-read (CWE-126).
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