Changes

| [[User:Yellows8|Yellows8]]

| [[User:Yellows8|Yellows8]]

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| Extdata SaveData.dat loading buffer overflow

| Extdata file-data loading buffer overflow

| The extdata SaveData.dat file-reading code allocates a fixed-size heap buffer for the expected SaveData.dat filesize, then reads the filedata into this buffer using the actual FS filesize. Before v5.0 the filesize used here wasn't validated, hence if the filesize is larger than alloc_size a buffer overflow would occur. ''After'' doing the file-read it does validate that the actual_readsize matches the alloc_size, but at this point the buffer overflow has already occurred.

| The extdata file-reading code allocates a fixed-size heap buffer for the expected filesize, then reads the filedata into this buffer using the actual FS filesize. Before v5.0 the filesize used here wasn't validated, hence if the filesize is larger than alloc_size a buffer overflow would occur. ''After'' doing the file-read it does validate that the actual_readsize matches the alloc_size, but at this point the buffer overflow has already occurred.

It's unknown whether v5.0 had similar changes for other extdata file-loading code.

This affected at least the following: SaveData.dat and Cache.dat.

This can be triggered by installing a <v4.0 Home Menu version, with Home Menu extdata from >=v4.0 still on SD. When this is done with v2.0 Home Menu, a kernelpanic occurs when processing an AM command(it appears a buffer ptr which is then passed to a command was overwritten with 0x0 - of course other SaveData.dat filesizes may result in different behaviour).

This can be triggered with SaveData.dat by installing a <v4.0 Home Menu version, with Home Menu extdata from >=v4.0 still on SD. When this is done with v2.0 Home Menu, a kernelpanic occurs when processing an AM command(it appears a buffer ptr which is then passed to a command was overwritten with 0x0 - of course other SaveData.dat filesizes may result in different behaviour).

| [[5.0.0-11|5.0.0-X]]

| [[5.0.0-11|5.0.0-X]]

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