CVE-2024-35825
usb: gadget: ncm: Fix handling of zero block length packets
Severity Score
Exploit Likelihood
Affected Versions
Public Exploits
0Exploited in Wild
-Decision
Descriptions
In the Linux kernel, the following vulnerability has been resolved:
usb: gadget: ncm: Fix handling of zero block length packets
While connecting to a Linux host with CDC_NCM_NTB_DEF_SIZE_TX
set to 65536, it has been observed that we receive short packets,
which come at interval of 5-10 seconds sometimes and have block
length zero but still contain 1-2 valid datagrams present.
According to the NCM spec:
"If wBlockLength = 0x0000, the block is terminated by a
short packet. In this case, the USB transfer must still
be shorter than dwNtbInMaxSize or dwNtbOutMaxSize. If
exactly dwNtbInMaxSize or dwNtbOutMaxSize bytes are sent,
and the size is a multiple of wMaxPacketSize for the
given pipe, then no ZLP shall be sent.
wBlockLength= 0x0000 must be used with extreme care, because
of the possibility that the host and device may get out of
sync, and because of test issues.
wBlockLength = 0x0000 allows the sender to reduce latency by
starting to send a very large NTB, and then shortening it when
the sender discovers that there’s not sufficient data to justify
sending a large NTB"
However, there is a potential issue with the current implementation,
as it checks for the occurrence of multiple NTBs in a single
giveback by verifying if the leftover bytes to be processed is zero
or not. If the block length reads zero, we would process the same
NTB infintely because the leftover bytes is never zero and it leads
to a crash. Fix this by bailing out if block length reads zero.
En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: usb: gadget: ncm: corregido el manejo de paquetes de longitud de bloque cero Al conectarnos a un host Linux con CDC_NCM_NTB_DEF_SIZE_TX configurado en 65536, se ha observado que recibimos paquetes cortos, que vienen en intervalo de 5 a 10 segundos a veces y tiene una longitud de bloque cero, pero aún contiene 1 o 2 datagramas válidos presentes. Según la especificación NCM: "Si wBlockLength = 0x0000, el bloque finaliza con un paquete corto. En este caso, la transferencia USB aún debe ser más corta que dwNtbInMaxSize o dwNtbOutMaxSize. Si se envían exactamente bytes dwNtbInMaxSize o dwNtbOutMaxSize, y el tamaño es un múltiplo de wMaxPacketSize para la pipe dada, entonces no se enviará ningún ZLP. wBlockLength= 0x0000 debe usarse con extremo cuidado, debido a la posibilidad de que el host y el dispositivo no estén sincronizados y debido a problemas de prueba con wBlockLength = 0x0000. permite al remitente reducir la latencia comenzando a enviar un NTB muy grande y luego acortándolo cuando el remitente descubre que no hay datos suficientes para justificar el envío de un NTB grande". Sin embargo, existe un problema potencial con la implementación actual, ya que verifica para la aparición de múltiples NTB en una sola devolución verificando si los bytes sobrantes a procesar son cero o no. Si la longitud del bloque es cero, procesaríamos el mismo NTB infinitamente porque los bytes sobrantes nunca son cero y provocan un bloqueo. Solucione este problema rescatando si la longitud del bloque es cero.
CVSS Scores
SSVC
- Decision:Track
Timeline
- 2024-05-17 CVE Reserved
- 2024-05-17 CVE Published
- 2024-05-18 EPSS Updated
- 2024-12-19 CVE Updated
- ---------- Exploited in Wild
- ---------- KEV Due Date
- ---------- First Exploit
CWE
CAPEC
References (18)
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Affected Vendors, Products, and Versions
Vendor | Product | Version | Other | Status | ||||||
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Vendor | Product | Version | Other | Status | <-- --> | Vendor | Product | Version | Other | Status |
Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | >= 4.19.297 < 4.19.312 Search vendor "Linux" for product "Linux Kernel" and version " >= 4.19.297 < 4.19.312" | en |
Affected
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Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | >= 5.4.259 < 5.4.274 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.4.259 < 5.4.274" | en |
Affected
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Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | >= 5.10.199 < 5.10.215 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.10.199 < 5.10.215" | en |
Affected
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Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | >= 5.15.136 < 5.15.154 Search vendor "Linux" for product "Linux Kernel" and version " >= 5.15.136 < 5.15.154" | en |
Affected
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Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | >= 6.1.59 < 6.1.84 Search vendor "Linux" for product "Linux Kernel" and version " >= 6.1.59 < 6.1.84" | en |
Affected
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Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | >= 6.6 < 6.6.24 Search vendor "Linux" for product "Linux Kernel" and version " >= 6.6 < 6.6.24" | en |
Affected
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Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | >= 6.6 < 6.7.12 Search vendor "Linux" for product "Linux Kernel" and version " >= 6.6 < 6.7.12" | en |
Affected
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Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | >= 6.6 < 6.8 Search vendor "Linux" for product "Linux Kernel" and version " >= 6.6 < 6.8" | en |
Affected
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Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | 4.14.328 Search vendor "Linux" for product "Linux Kernel" and version "4.14.328" | en |
Affected
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Linux Search vendor "Linux" | Linux Kernel Search vendor "Linux" for product "Linux Kernel" | 6.5.8 Search vendor "Linux" for product "Linux Kernel" and version "6.5.8" | en |
Affected
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